## Cygwin Utilities

Cygwin comes with a number of command-line utilities that are used to manage the UNIX emulation portion of the Cygwin environment. While many of these reflect their UNIX counterparts, each was written specifically for Cygwin. You may use the long or short option names interchangeably; for example, --help and -h function identically. All of the Cygwin command-line utilities support the --help and --version options.

### cygcheck

Usage: cygcheck [-v] [-h] PROGRAM
cygcheck -c [-d] [PACKAGE]
cygcheck -s [-r] [-v] [-h]
cygcheck -k
cygcheck -f FILE [FILE]...
cygcheck -l [PACKAGE]...
cygcheck -p REGEXP
cygcheck --delete-orphaned-installation-keys
cygcheck --enable-unique-object-names Cygwin-DLL
cygcheck --disable-unique-object-names Cygwin-DLL
cygcheck --show-unique-object-names Cygwin-DLL
cygcheck -h

List system information, check installed packages, or query package database.

At least one command option or a PROGRAM is required, as shown above.

PROGRAM              list library (DLL) dependencies of PROGRAM
-c, --check-setup    show installed version of PACKAGE and verify integrity
(or for all installed packages if none specified)
-d, --dump-only      just list packages, do not verify (with -c)
-s, --sysinfo        produce diagnostic system information (implies -c -d)
-r, --registry       also scan registry for Cygwin settings (with -s)
-k, --keycheck       perform a keyboard check session (must be run from a
plain console only, not from a pty/rxvt/xterm)
-f, --find-package   find the package to which FILE belongs
-l, --list-package   list contents of PACKAGE (or all packages if none given)
-p, --package-query  search for REGEXP in the entire cygwin.com package
repository (requires internet connectivity)
--delete-orphaned-installation-keys
Delete installation keys of old, now unused
installations from the registry.  Requires the right
to change the registry.
--enable-unique-object-names Cygwin-DLL
--disable-unique-object-names Cygwin-DLL
--show-unique-object-names Cygwin-DLL
Enable, disable, or show the setting of the
\"unique object names\" setting in the Cygwin DLL
given as argument to this option.  The DLL path must
be given as valid Windows(!) path.
If you don't know what this means, don't change it.
-v, --verbose        produce more verbose output
-h, --help           annotate output with explanatory comments when given
with another command, otherwise print this help
-V, --version        print the version of cygcheck and exit

Note: -c, -f, and -l only report on packages that are currently installed. To
search all official Cygwin packages use -p instead.  The -p REGEXP matches
package names, descriptions, and names of files/paths within all packages.


The cygcheck program is a diagnostic utility for dealing with Cygwin programs. If you are familiar with dpkg or rpm, cygcheck is similar in many ways. (The major difference is that setup.exe handles installing and uninstalling packages; see the section called “Internet Setup” for more information.)

The -c option checks the version and status of installed Cygwin packages. If you specify one or more package names, cygcheck will limit its output to those packages, or with no arguments it lists all packages. A package will be marked Incomplete if files originally installed are no longer present. The best thing to do in that situation is reinstall the package with setup.exe. To see which files are missing, use the -v option. If you do not need to know the status of each package and want cygcheck to run faster, add the -d option and cygcheck will only output the name and version for each package.

If you list one or more programs on the command line, cygcheck will diagnose the runtime environment of that program or programs, providing the names of DLL files on which the program depends. If you specify the -s option, cygcheck will give general system information. If you list one or more programs on the command line and specify -s, cygcheck will report on both.

The -f option helps you to track down which package a file came from, and -l lists all files in a package. For example, to find out about /usr/bin/less and its package:

Example 3.3. Example cygcheck usage

$cygcheck -f /usr/bin/less less-381-1$ cygcheck -l less
/usr/bin/less.exe
/usr/bin/lessecho.exe
/usr/bin/lesskey.exe
/usr/man/man1/less.1
/usr/man/man1/lesskey.1


The -h option prints additional helpful messages in the report, at the beginning of each section. It also adds table column headings. While this is useful information, it also adds some to the size of the report, so if you want a compact report or if you know what everything is already, just leave this out.

The -v option causes the output to be more verbose. What this means is that additional information will be reported which is usually not interesting, such as the internal version numbers of DLLs, additional information about recursive DLL usage, and if a file in one directory in the PATH also occurs in other directories on the PATH.

The -r option causes cygcheck to search your registry for information that is relevant to Cygwin programs. These registry entries are the ones that have "Cygwin" in the name. If you are paranoid about privacy, you may remove information from this report, but please keep in mind that doing so makes it harder to diagnose your problems.

In contrast to the other options that search the packages that are installed on your local system, the -p option can be used to search the entire official Cygwin package repository. It takes as argument a Perl-compatible regular expression which is used to match package names, package descriptions, and path/filenames of the contents of packages. This feature requires an active internet connection, since it must query the cygwin.com web site. In fact, it is equivalent to the search that is available on the Cygwin package listing page.

For example, perhaps you are getting an error because you are missing a certain DLL and you want to know which package includes that file:

Example 3.4. Searching all packages for a file

$cygcheck -p 'cygintl-2\.dll' Found 1 matches for 'cygintl-2\.dll'. libintl2-0.12.1-3 GNU Internationalization runtime library$ cygcheck -p 'libexpat.*\.a'
Found 2 matches for 'libexpat.*\.a'.

expat-1.95.7-1            XML parser library written in C
expat-1.95.8-1            XML parser library written in C

$cygcheck -p '/ls\.exe' Found 2 matches for '/ls\.exe'. coreutils-5.2.1-5 GNU core utilities (includes fileutils, sh-utils and textutils) coreutils-5.3.0-6 GNU core utilities (includes fileutils, sh-utils and textutils)  Note that this option takes a regular expression, not a glob or wildcard. This means that you need to use .* if you want something similar to the wildcard * commonly used in filename globbing. Similarly, to match the period character you should use \. since the . character in a regexp is a metacharacter that will match any character. Also be aware that the characters such as \ and * are shell metacharacters, so they must be either escaped or quoted, as in the example above. The third example above illustrates that if you want to match a whole filename, you should include the / path seperator. In the given example this ensures that filenames that happen to end in ls.exe such as ncftpls.exe are not shown. Note that this use does not mean "look for packages with ls in the root directory," since the / can match anywhere in the path. It's just there to anchor the match so that it matches a full filename. By default the matching is case-sensitive. To get a case insensitive match, begin your regexp with (?i) which is a PCRE-specific feature. For complete documentation on Perl-compatible regular expression syntax and options, read the perlre manpage, or one of many websites such as perldoc.com that document the Perl language. The cygcheck program should be used to send information about your system for troubleshooting when requested. When asked to run this command save the output so that you can email it, for example: $ cygcheck -s -v -r -h > cygcheck_output.txt


Each Cygwin DLL stores its path and installation key in the registry. This allows troubleshooting of problems which could be a result of having multiple concurrent Cygwin installations. However, if you're experimenting a lot with different Cygwin installation paths, your registry could accumulate a lot of old Cygwin installation entries for which the installation doesn't exist anymore. To get rid of these orphaned registry entries, use the cygcheck --delete-orphaned-installation-keys command.

Each Cygwin DLL generates a key value from its installation path. This value is not only stored in the registry, it's also used to generate global object names used for interprocess communication. This keeps different Cygwin installations separate. Processes running under a Cygwin DLL installed in C:\cygwin don't see processes running under a Cygwin DLL installed in C:\Program Files\cygwin. This allows running multiple versions of Cygwin DLLs without these versions to interfere with each other, or to run small third-party installations for a specific purpose independently from a Cygwin net distribution.

For debugging purposes it could be desired that the various Cygwin DLLs use the same key, independently from their installation paths. If the DLLs have different versions, trying to run processes under these DLLs concurrently will result in error messages like this one:

*** shared version mismatch detected - 0x8A88009C/0x75BE0074.
This problem is probably due to using incompatible versions of the Cygwin DLL.
Search for cygwin1.dll using the Windows Start->Find/Search facility
reside in x:\\cygwin\\bin, where 'x' is the drive on which you have
installed the cygwin distribution.  Rebooting is also suggested if you
are unable to find another Cygwin DLL.


To disable the usage of a unique key value of a certain Cygwin DLL, use the cygcheck --disable-unique-object-names Cygwin-DLL command. Cygwin-DLL is the Windows path (*not* a Cygwin POSIX path) to the DLL for which you want to disable this feature. Note that you have to stop all Cygwin processes running under this DLL, before you're allowed to change this setting. For instance, run cygcheck from a DOS command line for this purpose.

To re-enable the usage of a unique key, use the cygcheck --enable-unique-object-names Cygwin-DLL command. This option has the same characteristics as the --disable-unique-object-names option

Finally, you can use cygcheck --show-unique-object-names Cygwin-DLL to find out if the given Cygwin DLL use unique object names or not. In contrast to the --disable-... and --enable-... options, the --show-unique-object-names option also works for Cygwin DLLs which are currently in use.

### cygpath

Usage: cygpath (-d|-m|-u|-w|-t TYPE) [-f FILE] [OPTION]... NAME...
cygpath [-c HANDLE]
cygpath [-F ID]

Convert Unix and Windows format paths, or output system path information

Output type options:

-d, --dos             print DOS (short) form of NAMEs (C:\PROGRA~1\)
-m, --mixed           like --windows, but with regular slashes (C:/WINNT)
-M, --mode            report on mode of file (currently binmode or textmode)
-u, --unix            (default) print Unix form of NAMEs (/cygdrive/c/winnt)
-w, --windows         print Windows form of NAMEs (C:\WINNT)
-t, --type TYPE       print TYPE form: 'dos', 'mixed', 'unix', or 'windows'

Path conversion options:

-a, --absolute        output absolute path
-l, --long-name       print Windows long form of NAMEs (with -w, -m only)
-p, --path            NAME is a PATH list (i.e., '/bin:/usr/bin')
-s, --short-name      print DOS (short) form of NAMEs (with -w, -m only)
-C, --codepage CP     print DOS, Windows, or mixed pathname in Windows
codepage CP.  CP can be a numeric codepage identifier,
or one of the reserved words ANSI, OEM, or UTF8.
If this option is missing, cygpath defaults to the
character set defined by the current locale.

System information:

-A, --allusers        use All Users' instead of current user for -D, -P
-D, --desktop         output Desktop' directory and exit
-H, --homeroot        output Profiles' directory (home root) and exit
-O, --mydocs          output My Documents' directory and exit
-P, --smprograms      output Start Menu Programs' directory and exit
-S, --sysdir          output system directory and exit
-W, --windir          output Windows' directory and exit
-F, --folder ID       output special folder with numeric ID and exit

Other options:

-f, --file FILE       read FILE for input; use - to read from STDIN
-o, --option          read options from FILE as well (for use with --file)
-c, --close HANDLE    close HANDLE (for use in captured process)
-i, --ignore          ignore missing argument
-h, --help            output usage information and exit
-V, --version         output version information and exit


The cygpath program is a utility that converts Windows native filenames to Cygwin POSIX-style pathnames and vice versa. It can be used when a Cygwin program needs to pass a file name to a native Windows program, or expects to get a file name from a native Windows program. Alternatively, cygpath can output information about the location of important system directories in either format.

The -u and -w options indicate whether you want a conversion to UNIX (POSIX) format (-u) or to Windows format (-w). Use the -d to get DOS-style (8.3) file and path names. The -m option will output Windows-style format but with forward slashes instead of backslashes. This option is especially useful in shell scripts, which use backslashes as an escape character.

In combination with the -w option, you can use the -l and -s options to use normal (long) or DOS-style (short) form. The -d option is identical to -w and -s together.

The -C option allows to specify a Windows codepage to print DOS and Windows paths created with one of the -d, -m, or -w options. The default is to use the character set of the current locale defined by one of the internationalization environment variables LC_ALL, LC_CTYPE, or LANG, see the section called “Internationalization”. This is sometimes not sufficient for interaction with native Windows tools, which might expect native, non-ASCII characters in a specific Windows codepage. Console tools, for instance, might expect pathnames in the current OEM codepage, while graphical tools like Windows Explorer might expect pathnames in the current ANSI codepage.

The -C option takes a single parameter:

• ANSI, to specify the current ANSI codepage

• OEM, to specify the current OEM (console) codepage

• UTF8, to specify UTF-8.

• A numerical, decimal codepage number, for instance 936 for GBK, 28593 for ISO-8859-3, etc. A full list of supported codepages is listed on the Microsoft MSDN page Code Page Identifiers. A codepage of 0 is the same as if the -C hasn't been specified at all.

The -p option means that you want to convert a path-style string rather than a single filename. For example, the PATH environment variable is semicolon-delimited in Windows, but colon-delimited in UNIX. By giving -p you are instructing cygpath to convert between these formats.

The -i option supresses the print out of the usage message if no filename argument was given. It can be used in make file rules converting variables that may be omitted to a proper format. Note that cygpath output may contain spaces (C:\Program Files) so should be enclosed in quotes.

Example 3.5. Example cygpath usage


#!/bin/sh
if [ "${1}" = "" ]; then XPATH="."; else XPATH="$(cygpath -C ANSI -w "${1}")"; fi explorer$XPATH &



The capital options -D, -H, -P, -S, and -W output directories used by Windows that are not the same on all systems, for example -S might output C:\WINNT\system32 or C:\Windows\System32. The -H shows the Windows profiles directory that can be used as root of home. The -A option forces use of the "All Users" directories instead of the current user for the -D, -O and -P options. The -F outputs other special folders specified by their internal numeric code (decimal or 0x-prefixed hex). For valid codes and symbolic names, see the CSIDL_* definitions in the include file /usr/include/w32api/shlobj.h from package w32api. The current valid range of codes for folders is 0 (Desktop) to 59 (CDBurn area). By default the output is in UNIX (POSIX) format; use the -w or -d options to get other formats.

### dumper

Usage: dumper [OPTION] FILENAME WIN32PID

Dump core from WIN32PID to FILENAME.core

-d, --verbose  be verbose while dumping
-h, --help     output help information and exit
-q, --quiet    be quiet while dumping (default)
-V, --version  output version information and exit


The dumper utility can be used to create a core dump of running Windows process. This core dump can be later loaded to gdb and analyzed. One common way to use dumper is to plug it into cygwin's Just-In-Time debugging facility by adding

error_start=x:\path\to\dumper.exe


to the CYGWIN environment variable. Please note that x:\path\to\dumper.exe is Windows-style and not cygwin path. If error_start is set this way, then dumper will be started whenever some program encounters a fatal error.

dumper can be also be started from the command line to create a core dump of any running process. Unfortunately, because of a Windows API limitation, when a core dump is created and dumper exits, the target process is terminated too.

To save space in the core dump, dumper doesn't write those portions of target process' memory space that are loaded from executable and dll files and are unchangeable, such as program code and debug info. Instead, dumper saves paths to files which contain that data. When a core dump is loaded into gdb, it uses these paths to load appropriate files. That means that if you create a core dump on one machine and try to debug it on another, you'll need to place identical copies of the executable and dlls in the same directories as on the machine where the core dump was created.

### getconf

Usage: getconf [-v specification] variable_name [pathname]
getconf -a [pathname]

Get configuration values

-v specification     Indicate specific version for which configuration
values shall be fetched.
-a, --all            Print all known configuration values

Other options:

-h, --help           This text
-V, --version        Print program version and exit


The getconf utility prints the value of the configuration variable specified by variable_name. If no pathname is given, getconf serves as a wrapper for the confstr and sysconf functions, supporting the symbolic constants defined in the limits.h and unistd.h headers, without their respective _CS_ or _SC_ prefixes.

If pathname is given, getconf prints the value of the configuration variable for the specified pathname. In this form, getconf serves as a wrapper for the pathconf function, supporting the symbolic constants defined in the unistd.h header, without the _PC_ prefix.

If you specify the -v option, the parameter denotes a specification for which the value of the configuration variable should be printed. Note that the only specifications supported by Cygwin are POSIX_V7_ILP32_OFFBIG and the legacy POSIX_V6_ILP32_OFFBIG and XBS5_ILP32_OFFBIG equivalents.

Use the -a option to print a list of all available configuration variables for the system, or given pathname, and their values.

### getfacl

Usage: getfacl [-adn] FILE [FILE2...]

Display file and directory access control lists (ACLs).

-a, --access   display the file access control list
-d, --default  display the default access control list
-h, --help     print help explaining the command line options
-n, --noname   display user and group IDs instead of names
-V, --version  output version information and exit

When multiple files are specified on the command line, a blank
line separates the ACLs for each file.


For each argument that is a regular file, special file or directory, getfacl displays the owner, the group, and the ACL. For directories getfacl displays additionally the default ACL. With no options specified, getfacl displays the filename, the owner, the group, the setuid (s), setgid (s), and sticky (t) bits if available, and both the ACL and the default ACL, if it exists. For more information on Cygwin and Windows ACLs, see the section called “POSIX accounts, permission, and security” in the Cygwin User's Guide. The format for ACL output is as follows:

     # file: filename
# owner: name or uid
# group: name or uid
# flags: sst
user::perm
user:name or uid:perm
group::perm
group:name or gid:perm
other:perm
default:user::perm
default:user:name or uid:perm
default:group::perm
default:group:name or gid:perm
default:other:perm


### kill

Usage: kill [-f] [-signal] [-s signal] pid1 [pid2 ...]
kill -l [signal]

Send signals to processes

-f, --force     force, using win32 interface if necessary
-l, --list      print a list of signal names
-s, --signal    send signal (use kill --list for a list)
-h, --help      output usage information and exit
-V, --version   output version information and exit


The kill program allows you to send arbitrary signals to other Cygwin programs. The usual purpose is to end a running program from some other window when ^C won't work, but you can also send program-specified signals such as SIGUSR1 to trigger actions within the program, like enabling debugging or re-opening log files. Each program defines the signals they understand.

You may need to specify the full path to use kill from within some shells, including bash, the default Cygwin shell. This is because bash defines a kill builtin function; see the bash man page under BUILTIN COMMANDS for more information. To make sure you are using the Cygwin version, try

$/bin/kill --version  which should give the Cygwin kill version number and copyright information. Unless you specific the -f option, the "pid" values used by kill are the Cygwin pids, not the Windows pids. To get a list of running programs and their Cygwin pids, use the Cygwin ps program. ps -W will display all windows pids. The kill -l option prints the name of the given signal, or a list of all signal names if no signal is given. To send a specific signal, use the -signN option, either with a signal number or a signal name (minus the "SIG" part), as shown in these examples: Example 3.6. Using the kill command $ kill 123
$ kill -1 123 $ kill -HUP 123
$ kill -f 123  Here is a list of available signals, their numbers, and some commentary on them, from the file <sys/signal.h>, which should be considered the official source of this information. SIGHUP 1 hangup SIGINT 2 interrupt SIGQUIT 3 quit SIGILL 4 illegal instruction (not reset when caught) SIGTRAP 5 trace trap (not reset when caught) SIGABRT 6 used by abort SIGEMT 7 EMT instruction SIGFPE 8 floating point exception SIGKILL 9 kill (cannot be caught or ignored) SIGBUS 10 bus error SIGSEGV 11 segmentation violation SIGSYS 12 bad argument to system call SIGPIPE 13 write on a pipe with no one to read it SIGALRM 14 alarm clock SIGTERM 15 software termination signal from kill SIGURG 16 urgent condition on IO channel SIGSTOP 17 sendable stop signal not from tty SIGTSTP 18 stop signal from tty SIGCONT 19 continue a stopped process SIGCHLD 20 to parent on child stop or exit SIGCLD 20 System V name for SIGCHLD SIGTTIN 21 to readers pgrp upon background tty read SIGTTOU 22 like TTIN for output if (tp->t_local&LTOSTOP) SIGIO 23 input/output possible SIGPOLL 23 System V name for SIGIO SIGXCPU 24 exceeded CPU time limit SIGXFSZ 25 exceeded file size limit SIGVTALRM 26 virtual time alarm SIGPROF 27 profiling time alarm SIGWINCH 28 window changed SIGLOST 29 resource lost (eg, record-lock lost) SIGPWR 29 power failure SIGUSR1 30 user defined signal 1 SIGUSR2 31 user defined signal 2  ### ldd Usage: ldd [OPTION]... FILE... Print shared library dependencies -h, --help print this help and exit -V, --version print version information and exit -r, --function-relocs process data and function relocations (currently unimplemented) -u, --unused print unused direct dependencies (currently unimplemented) -v, --verbose print all information (currently unimplemented)  ldd prints the shared libraries (DLLs) an executable or DLL is linked against. No modifying option is implemented yet. ### locale Usage: locale [-amvhV] or: locale [-ck] NAME or: locale [-usfnU] Get locale-specific information. System information: -a, --all-locales List all available supported locales -m, --charmaps List all available character maps -v, --verbose More verbose output Modify output format: -c, --category-name List information about given category NAME -k, --keyword-name Print information about given keyword NAME Default locale information: -u, --user Print locale of user's default UI language -s, --system Print locale of system default UI language -f, --format Print locale of user's regional format settings (time, numeric & monetary) -n, --no-unicode Print system default locale for non-Unicode programs -U, --utf Attach \".UTF-8\" to the result Other options: -h, --help This text -V, --version Print program version and exit  locale without parameters prints information about the current locale environment settings. The -u, -s, -f, and -n options can be used to request the various Windows locale settings. The purpose is to use this command in scripts to set the POSIX locale variables. The -u option prints the current user's Windows UI locale to stdout. In Windows Vista and Windows 7 this setting is called the "Display Language"; there was no corresponding user setting in Windows XP. The -s option prints the systems default instead. The -f option prints the user's setting for time, date, number and currency. That's equivalent to the setting in the "Formats" or "Regional Options" tab in the "Region and Language" or "Regional and Language Options" dialog. With the -U option locale appends a ".UTF-8". Usage example: bash$ export LANG=$(locale -uU) bash$ echo $LANG en_US.UTF-8 bash$ export LC_TIME=$(locale -fU) bash$ echo $LC_TIME de_DE.UTF-8  The -a option is helpful to learn which locales are supported by your Windows machine. It prints all available locales and the allowed modifiers. Example: bash$ locale -a
C
C.utf8
POSIX
af_ZA
af_ZA.utf8
am_ET
am_ET.utf8
...
be_BY
be_BY.utf8
be_BY@latin
...
ca_ES
ca_ES.utf8
ca_ES@euro
catalan
...


The -v option prints more detailed information about each available locale. Example:

bash$locale -av locale: af_ZA archive: /cygdrive/c/Windows/system32/kernel32.dll ------------------------------------------------------------------------------- language | Afrikaans territory | South Africa codeset | ISO-8859-1 locale: af_ZA.utf8 archive: /cygdrive/c/Windows/system32/kernel32.dll ------------------------------------------------------------------------------- language | Afrikaans territory | South Africa codeset | UTF-8 ... locale: ca_ES@euro archive: /cygdrive/c/Windows/system32/kernel32.dll ------------------------------------------------------------------------------- language | Catalan territory | Spain codeset | ISO-8859-15 locale: catalan archive: /usr/share/locale/locale.alias ------------------------------------------------------------------------------- language | Catalan territory | Spain codeset | ISO-8859-1 ...  The -m option prints the names of the available charmaps supported by Cygwin to stdout. Otherwise, if arguments are given, locale prints the values assigned to these arguments. Arguments can be names of locale categories (for instance: LC_CTYPE, LC_MONETARY), or names of keywords supported in the locale categories (for instance: thousands_sep, charmap). The -c option prints additionally the name of the category. The -k option prints additionally the name of the keyword. Example: bash$ locale -ck LC_MESSAGES
LC_MESSAGES
yesexpr="^[yY]"
noexpr="^[nN]"
yesstr="yes"
nostr="no"
messages-codeset="UTF-8"
bash$locale noexpr ^[nN]  ### minidumper Usage: minidumper [OPTION] FILENAME WIN32PID Write minidump from WIN32PID to FILENAME.dmp -t, --type minidump type flags -n, --nokill don't terminate the dumped process -d, --verbose be verbose while dumping -h, --help output help information and exit -q, --quiet be quiet while dumping (default) -V, --version output version information and exit  The minidumper utility can be used to create a minidump of a running Windows process. This minidump can be later analysed using breakpad or Windows debugging tools. minidumper can be used with cygwin's Just-In-Time debugging facility in exactly the same way as dumper (See the section called “dumper”). minidumper can also be started from the command line to create a minidump of any running process. For compatibility with dumper the target process is terminated after dumping unless the -n option is given. ### mkgroup Usage: mkgroup [OPTION]... Write /etc/group-like output to stdout Don't use this command to generate a local /etc/group file, unless you really need one. See the Cygwin User's Guide for more information. Options: -l,--local [machine] Print local group accounts of \"machine\", from local machine if no machine specified. Automatically adding machine prefix for local machine depends on settings in /etc/nsswitch.conf. -L,--Local machine Ditto, but generate groupname with machine prefix. -d,--domain [domain] Print domain groups, from current domain if no domain specified. -c,--current Print current group. -S,--separator char For -L use character char as domain\\group separator in groupname instead of default '+'. -o,--id-offset offset Change the default offset (0x10000) added to gids -g,--group groupname Only return information for the specified group. One of -l, -d must be specified, too. -b,--no-builtin Don't print BUILTIN groups. -U,--unix grouplist Print UNIX groups when using -l on a UNIX Samba server. Grouplist is a comma-separated list of groupnames or gid ranges (root,-25,50-100). Enumerating large ranges can take a long time! -h,--help Print this message. -v,--version Print version information and exit. Default is to print local groups on stand-alone machines, plus domain groups on domain controllers and domain member machines.  The mkgroup program can be used to create a local /etc/group file. Cygwin doesn't need this file, because it reads group information from the Windows account databases, but you can add an /etc/group file for instance, if your machine is often disconnected from its domain controller. Note that this information is static, in contrast to the information automatically gathered by Cygwin from the Windows account databases. If you change the group information on your system, you'll need to regenerate the group file for it to have the new information. By default, the information generated by mkgroup is equivalent to the information generated by Cygwin itself. The -d and -l/-L options allow you to specify where the information comes from, some domain, or the local SAM of a machine. Note that you can only enumerate accounts from trusted domains. Any non-trusted domain will be ignored. Access-restrictions of your current account apply. The -l/-L when used with a machine name, tries to contact that machine to enumerate local groups of other machines, typically outside of domains. This scenario cannot be covered by Cygwin's account automatism. If you want to use the -L option, but you don't like the default domain/group separator from /etc/nsswitch.conf, you can specify another separator using the -S option, for instance: Example 3.7. Setting up group entry for current user with different domain/group separator $ mkgroup -L server1 -S= > /etc/group


For very simple needs, an entry for the current user's group can be created by using the option -c.

The -o option allows for (unlikely) special cases with multiple machines where the GIDs might match otherwise. The -g option only prints the information for one group. The -U option allows you to enumerate the standard UNIX groups on a Samba machine. It's used together with -l samba-server or -L samba-server. The normal UNIX groups are usually not enumerated, but they can show up as a group in ls -l output.

### mkpasswd

Usage: mkpasswd [OPTIONS]...

Write /etc/passwd-like output to stdout

Don't use this command to generate a local /etc/passwd file, unless you

Options:

-l,--local [machine]    Print local user accounts of \"machine\",
from local machine if no machine specified.
Automatically adding machine prefix for local
machine depends on settings in /etc/nsswitch.conf.
-L,--Local machine      Ditto, but generate username with machine prefix.
-d,--domain [domain]    Print domain accounts,
from current domain if no domain specified.
-c,--current            Print current user.
-S,--separator char     For -L use character char as domain\\user
-o,--id-offset offset   Change the default offset (0x10000) added to uids
of foreign local machine accounts.  Use with -l/-L.
One of -l, -d must be specified, too
-b,--no-builtin         Don't print BUILTIN users.
-p,--path-to-home path  Use specified path instead of user account home dir
or /home prefix.
-U,--unix userlist      Print UNIX users when using -l on a UNIX Samba
server.  Userlist is a comma-separated list of
Enumerating large ranges can take a long time!
-h,--help               Displays this message.
-V,--version            Version information and exit.

Default is to print local accounts on stand-alone machines, domain accounts
on domain controllers and domain member machines.


The mkpasswd program can be used to create a /etc/passwd file. Cygwin doesn't need this file, because it reads user information from the Windows account databases, but you can add an /etc/passwd file, for instance if your machine is often disconnected from its domain controller.

Note that this information is static, in contrast to the information automatically gathered by Cygwin from the Windows account databases. If you change the user information on your system, you'll need to regenerate the passwd file for it to have the new information.

By default, the information generated by mkpasswd is equivalent to the information generated by Cygwin itself. The -d and -l/-L options allow you to specify where the information comes from, some domain, or the local SAM of a machine. Note that you can only enumerate accounts from trusted domains. Any non-trusted domain will be ignored. Access-restrictions of your current account apply. The -l/-L when used with a machine name, tries to contact that machine to enumerate local groups of other machines, typically outside of domains. This scenario cannot be covered by Cygwin's account automatism. If you want to use the -L option, but you don't like the default domain/group separator from /etc/nsswitch.conf, you can specify another separator using the -S option, analog to mkgroup.

For very simple needs, an entry for the current user can be created by using the option -c.

The -o option allows for special cases (such as multiple domains) where the UIDs might match otherwise. The -p option causes mkpasswd to use the specified prefix instead of the account home dir or /home/ . For example, this command:

Example 3.8. Using an alternate home root

$ mkpasswd -l -p "$(cygpath -H)" > /etc/passwd


would put local users' home directories in the Windows 'Profiles' directory. The -u option creates just an entry for the specified user. The -U option allows you to enumerate the standard UNIX users on a Samba machine. It's used together with -l samba-server or -L samba-server. The normal UNIX users are usually not enumerated, but they can show up as file owners in ls -l output.

### mount

Usage: mount [OPTION] [<win32path> <posixpath>]
mount -a
mount <posixpath>

Display information about mounted filesystems, or mount a filesystem

-a, --all                     mount all filesystems mentioned in fstab
-c, --change-cygdrive-prefix  change the cygdrive path prefix to <posixpath>
-f, --force                   force mount, don't warn about missing mount
point directories
-h, --help                    output usage information and exit
-m, --mount-entries           write fstab entries to replicate mount points
and cygdrive prefixes
-o, --options X[,X...]        specify mount options
-p, --show-cygdrive-prefix    show user and/or system cygdrive path prefix
-V, --version                 output version information and exit


The mount program is used to map your drives and shares onto Cygwin's simulated POSIX directory tree, much like as is done by mount commands on typical UNIX systems. However, in contrast to mount points given in /etc/fstab, mount points created or changed with mount are not persistent. They disappear immediately after the last process of the current user exited. Please see the section called “The Cygwin Mount Table” for more information on the concepts behind the Cygwin POSIX file system and strategies for using mounts. To remove mounts temporarily, use umount

#### Using mount

If you just type mount with no parameters, it will display the current mount table for you.

Example 3.9. Displaying the current set of mount points

$ mount C:/cygwin/bin on /usr/bin type ntfs (binary) C:/cygwin/lib on /usr/lib type ntfs (binary) C:/cygwin on / type ntfs (binary) C: on /mnt/c type ntfs (binary,user,noumount) D: on /mnt/d type fat (binary,user,noumount)  In this example, c:/cygwin is the POSIX root and the D drive is mapped to /mnt/d. Note that in this case, the root mount is a system-wide mount point that is visible to all users running Cygwin programs, whereas the /mnt/d mount is only visible to the current user. The mount utility is also the mechanism for adding new mounts to the mount table in memory. The following example demonstrates how to mount the directory //pollux/home/joe/data to /data for the duration of the current session. Example 3.10. Adding mount points $ ls /data
ls: /data: No such file or directory
$ mount //pollux/home/joe/data /data mount: warning - /data does not exist! $ mount
//pollux/home/joe/data on /data type smbfs (binary)
C:/cygwin/bin on /usr/bin type ntfs (binary)
C:/cygwin/lib on /usr/lib type ntfs (binary)
C:/cygwin on / type ntfs (binary)
C: on /c type ntfs (binary,user,noumount)
D: on /d type fat (binary,user,noumount)


A given POSIX path may only exist once in the mount table. Attempts to replace the mount will fail with a busy error. The -f (force) option causes the old mount to be silently replaced with the new one, provided the old mount point was a user mount point. It's not valid to replace system-wide mount points. Additionally, the -f option will silence warnings about the non-existence of directories at the Win32 path location.

The -o option is the method via which various options about the mount point may be recorded. The following options are available (note that most of the options are duplicates of other mount flags):

  acl        - Use the filesystem's access control lists (ACLs) to
implement real POSIX permissions (default).
binary     - Files default to binary mode (default).
bind       - Allows to remount part of the file hierarchy somewhere else.
Different from other mount calls, the first argument
specifies an absolute POSIX path, rather than a Win32 path.
This POSIX path is remounted to the POSIX path specified as
the second parameter.  The conversion to a Win32 path is done
within Cygwin immediately at the time of the call.  Note that
symlinks are ignored while performing this path conversion.
cygexec    - Treat all files below mount point as cygwin executables.
dos        - Always convert leading spaces and trailing dots and spaces to
characters in the UNICODE private use area.  This allows to use
broken filesystems which only allow DOS filenames, even if they
are not recognized as such by Cygwin.
exec       - Treat all files below mount point as executable.
ihash      - Always fake inode numbers rather than using the ones returned
by the filesystem.  This allows to use broken filesystems which
don't return unambiguous inode numbers, even if they are not
recognized as such by Cygwin.
noacl      - Ignore ACLs and fake POSIX permissions.
nosuid     - No suid files are allowed (currently unimplemented)
notexec    - Treat all files below mount point as not executable.
override   - Override immutable mount points.
posix=0    - Switch off case sensitivity for paths under this mount point.
posix=1    - Switch on case sensitivity for paths under this mount point
(default).
sparse     - Switch on support for sparse files.  This option only makes
sense on NTFS and then only if you really need sparse files.
text       - Files default to CRLF text mode line endings.


For a more complete description of the mount options and the /etc/fstab file, see the section called “The Cygwin Mount Table”.

Note that all mount points added with mount are user mount points. System mount points can only be specified in the /etc/fstab file.

If you added mount points to /etc/fstab or your /etc/fstab.d/<username> file, you can add these mount points to your current user session using the -a/--all option, or by specifing the posix path alone on the command line. As an example, consider you added a mount point with the POSIX path /my/mount. You can add this mount point with either one of the following two commands to your current user session.

$ mount /my/mount $ mount -a


The first command just adds the /my/mount mount point to your current session, the mount -a adds all new mount points to your user session.

If you change a mount point to point to another native path, or if you changed the flags of a mount point, you have to umount the mount point first, before you can add it again. Please note that all such added mount points are added as user mount points, and that the rule that system mount points can't be removed or replaced in a running session still applies.

To bind a POSIX path to another POSIX path, use the bind mount flag.

$ mount -o bind /var /usr/var  This command makes the file hirarchy under /var additionally available under /usr/var. The -m option causes the mount utility to output the current mount table in a series of fstab entries. You can save this output as a backup when experimenting with the mount table. Copy the output to /etc/fstab to restore the old state. It also makes moving your settings to a different machine much easier. #### Cygdrive mount points Whenever Cygwin cannot use any of the existing mounts to convert from a particular Win32 path to a POSIX one, Cygwin will, instead, convert to a POSIX path using a default mount point: /cygdrive. For example, if Cygwin accesses z:\foo and the z drive is not currently in the mount table, then z:\ will be accessible as /cygdrive/z. The mount utility can be used to change this default automount prefix through the use of the "--change-cygdrive-prefix" option. In the following example, we will set the automount prefix to /mnt: Example 3.11. Changing the default prefix $ mount --change-cygdrive-prefix /mnt


Note that the cygdrive prefix can be set both per-user and system-wide, and that as with all mounts, a user-specific mount takes precedence over the system-wide setting. The mount utility creates system-wide mounts by default if you do not specify a type. You can always see the user and system cygdrive prefixes with the -p option. Using the --options flag with --change-cygdrive-prefix makes all new automounted filesystems default to this set of options. For instance (using the short form of the command line flags)

Example 3.12. Changing the default prefix with specific mount options

$ mount -c /mnt -o binary,noacl  #### Limitations Limitations: there is a hard-coded limit of 64 mount points (up to Cygwin 1.7.9: 30 mount points). Also, although you can mount to pathnames that do not start with "/", there is no way to make use of such mount points. Normally the POSIX mount point in Cygwin is an existing empty directory, as in standard UNIX. If this is the case, or if there is a place-holder for the mount point (such as a file, a symbolic link pointing anywhere, or a non-empty directory), you will get the expected behavior. Files present in a mount point directory before the mount become invisible to Cygwin programs. It is sometimes desirable to mount to a non-existent directory, for example to avoid cluttering the root directory with names such as a, b, c pointing to disks. Although mount will give you a warning, most everything will work properly when you refer to the mount point explicitly. Some strange effects can occur however. For example if your current working directory is /dir, say, and /dir/mtpt is a mount point, then mtpt will not show up in an ls or echo * command and find . will not find mtpt. ### passwd Usage: passwd [OPTION] [USER] Change USER's password or password attributes. User operations: -l, --lock lock USER's account. -u, --unlock unlock USER's account. -c, --cannot-change USER can't change password. -C, --can-change USER can change password. -e, --never-expires USER's password never expires. -E, --expires USER's password expires according to system's password aging rule. -p, --pwd-not-required no password required for USER. -P, --pwd-required password is required for USER. -R, --reg-store-pwd enter password to store it in the registry for later usage by services to be able to switch to this user context with network credentials. System operations: -i, --inactive NUM set NUM of days before inactive accounts are disabled (inactive accounts are those with expired passwords). -n, --minage MINDAYS set system minimum password age to MINDAYS days. -x, --maxage MAXDAYS set system maximum password age to MAXDAYS days. -L, --length LEN set system minimum password length to LEN. Other options: -d, --logonserver SERVER connect to SERVER (e.g. domain controller). Usually not required. -S, --status display password status for USER (locked, expired, etc.) plus global system password settings. -h, --help output usage information and exit. -V, --version output version information and exit. If no option is given, change USER's password. If no user name is given, operate on current user. System operations must not be mixed with user operations. Don't specify a USER when triggering a system operation. Don't specify a user or any other option together with the -R option. Non-Admin users can only store their password if cygserver is running. Note that storing even obfuscated passwords in the registry is not overly secure. Use this feature only if the machine is adequately locked down. Don't use this feature if you don't need network access within a remote session. You can delete your stored password by using passwd -R' and specifying an empty password.  passwd changes passwords for user accounts. A normal user may only change the password for their own account, but administrators may change passwords on any account. passwd also changes account information, such as password expiry dates and intervals. For password changes, the user is first prompted for their old password, if one is present. This password is then encrypted and compared against the stored password. The user has only one chance to enter the correct password. The administrators are permitted to bypass this step so that forgotten passwords may be changed. The user is then prompted for a replacement password. passwd will prompt twice for this replacement and compare the second entry against the first. Both entries are required to match in order for the password to be changed. After the password has been entered, password aging information is checked to see if the user is permitted to change their password at this time. If not, passwd refuses to change the password and exits. To get current password status information, use the -S option. Administrators can use passwd to perform several account maintenance functions (users may perform some of these functions on their own accounts). Accounts may be locked with the -l flag and unlocked with the -u flag. Similarly, -c disables a user's ability to change passwords, and -C allows a user to change passwords. For password expiry, the -e option disables expiration, while the -E option causes the password to expire according to the system's normal aging rules. Use -p to disable the password requirement for a user, or -P to require a password. Administrators can also use passwd to change system-wide password expiry and length requirements with the -i, -n, -x, and -L options. The -i option is used to disable an account after the password has been expired for a number of days. After a user account has had an expired password for NUM days, the user may no longer sign on to the account. The -n option is used to set the minimum number of days before a password may be changed. The user will not be permitted to change the password until MINDAYS days have elapsed. The -x option is used to set the maximum number of days a password remains valid. After MAXDAYS days, the password is required to be changed. Allowed values for the above options are 0 to 999. The -L option sets the minimum length of allowed passwords for users who don't belong to the administrators group to LEN characters. Allowed values for the minimum password length are 0 to 14. In any of the above cases, a value of 0 means no restrictions'. All operations affecting the current user are by default run against the logon server of the current user (taken from the environment variable LOGONSERVER. When password or account information of other users should be changed, the logon server is evaluated automatically. In rare cases, it might be necessary to switch to another domain controller to perform the action. In this case, use the -d option to specify the machine to run the command against. Note that the current user must have account operator permissions to perform user account changes in a domain. Users can use the passwd -R to enter a password which then gets stored in a special area of the registry on the local system, which is also used by Windows to store passwords of accounts running Windows services. When a privileged Cygwin application calls the set{e}uid(user_id) system call, Cygwin checks if a password for that user has been stored in this registry area. If so, it uses this password to switch to this user account using that password. This allows you to logon through, for instance, ssh with public key authentication and get a full qualified user token with all credentials for network access. However, the method has some drawbacks security-wise. This is explained in more detail in the section called “POSIX accounts, permission, and security”. Please note that storing passwords in that registry area is a privileged operation which only administrative accounts are allowed to do. Administrators can enter the password for other user accounts into the registry by specifying the username on the commandline. If normal, non-admin users should be allowed to enter their passwords using passwd -R, it's required to run cygserver as a service under the LocalSystem account before running passwd -R. This only affects storing passwords. Using passwords in privileged processes does not require cygserver to run. Limitations: Users may not be able to change their password on some systems. ### pldd Usage: pldd [OPTION...] PID List dynamic shared objects loaded into a process. -?, --help Give this help list --usage Give a short usage message -V, --version Print program version  pldd prints the shared libraries (DLLs) loaded by the process with the given PID. ### ps Usage: ps [-aefls] [-u UID] Report process status -a, --all show processes of all users -e, --everyone show processes of all users -f, --full show process uids, ppids -h, --help output usage information and exit -l, --long show process uids, ppids, pgids, winpids -p, --process show information for specified PID -s, --summary show process summary -u, --user list processes owned by UID -V, --version output version information and exit -W, --windows show windows as well as cygwin processes With no options, ps outputs the long format by default  The ps program gives the status of all the Cygwin processes running on the system (ps = "process status"). Due to the limitations of simulating a POSIX environment under Windows, there is little information to give. The PID column is the process ID you need to give to the kill command. The PPID is the parent process ID, and PGID is the process group ID. The WINPID column is the process ID displayed by NT's Task Manager program. The TTY column gives which pseudo-terminal a process is running on, or a '?' for services. The UID column shows which user owns each process. STIME is the time the process was started, and COMMAND gives the name of the program running. Listings may also have a status flag in column zero; S means stopped or suspended (in other words, in the background), I means waiting for input or interactive (foreground), and O means waiting to output. By default, ps will only show processes owned by the current user. With either the -a or -e option, all user's processes (and system processes) are listed. There are historical UNIX reasons for the synonomous options, which are functionally identical. The -f option outputs a "full" listing with usernames for UIDs. The -l option is the default display mode, showing a "long" listing with all the above columns. The other display option is -s, which outputs a shorter listing of just PID, TTY, STIME, and COMMAND. The -u option allows you to show only processes owned by a specific user. The -p option allows you to show information for only the process with the specified PID. The -W option causes ps show non-Cygwin Windows processes as well as Cygwin processes. The WINPID is also the PID, and they can be killed with the Cygwin kill command's -f option. ### regtool Usage: regtool [OPTION] (add|check|get|list|remove|unset|load|unload|save) KEY View or edit the Win32 registry Actions: add KEY\SUBKEY add new SUBKEY check KEY exit 0 if KEY exists, 1 if not get KEY\VALUE prints VALUE to stdout list KEY list SUBKEYs and VALUEs remove KEY remove KEY set KEY\VALUE [data ...] set VALUE unset KEY\VALUE removes VALUE from KEY load KEY\SUBKEY PATH load hive from PATH into new SUBKEY unload KEY\SUBKEY unload hive and remove SUBKEY save KEY\SUBKEY PATH save SUBKEY into new file PATH restore KEY\SUBKEY PATH restore SUBKEY from file PATH Options for 'list' Action: -k, --keys print only KEYs -l, --list print only VALUEs -p, --postfix like ls -p, appends '\' postfix to KEY names Options for 'get' Action: -b, --binary print REG_BINARY data as hex bytes -n, --none print data as stream of bytes as stored in registry -x, --hex print numerical data as hex numbers Options for 'set' Action: -b, --binary set type to REG_BINARY (hex args or '-') -D, --dword-be set type to REG_DWORD_BIG_ENDIAN -e, --expand-string set type to REG_EXPAND_SZ -i, --integer set type to REG_DWORD -m, --multi-string set type to REG_MULTI_SZ -n, --none set type to REG_NONE -Q, --qword set type to REG_QWORD -s, --string set type to REG_SZ Options for 'set' and 'unset' Actions: -K<c>, --key-separator[=]<c> set key separator to <c> instead of '\' Options for 'restore' action: -f, --force restore even if open handles exist at or beneath the location in the registry hierarchy to which KEY\SUBKEY points Other Options: -h, --help output usage information and exit -q, --quiet no error output, just nonzero return if KEY/VALUE missing -v, --verbose verbose output, including VALUE contents when applicable -w, --wow64 access 64 bit registry view (ignored on 32 bit Windows) -W, --wow32 access 32 bit registry view (ignored on 32 bit Windows) -V, --version output version information and exit KEY is in the format [host]\prefix\KEY\KEY\VALUE, where host is optional remote host in either \\hostname or hostname: format and prefix is any of: root HKCR HKEY_CLASSES_ROOT (local only) config HKCC HKEY_CURRENT_CONFIG (local only) user HKCU HKEY_CURRENT_USER (local only) machine HKLM HKEY_LOCAL_MACHINE users HKU HKEY_USERS You can use forward slash ('/') as a separator instead of backslash, in that case backslash is treated as escape character Example: regtool.exe get '\user\software\Microsoft\Clock\iFormat'  The regtool program allows shell scripts to access and modify the Windows registry. Note that modifying the Windows registry is dangerous, and carelessness here can result in an unusable system. Be careful. The -v option means "verbose". For most commands, this causes additional or lengthier messages to be printed. Conversely, the -q option supresses error messages, so you can use the exit status of the program to detect if a key exists or not (for example). The -w option allows you to access the 64 bit view of the registry. Several subkeys exist in a 32 bit and a 64 bit version when running on Windows 64. Since Cygwin is running in 32 bit mode, it only has access to the 32 bit view of these registry keys. When using the -w switch, the 64 bit view is used and regtool can access the entire registry. This option is simply ignored when running on 32 bit Windows versions. The -W option allows you to access the 32 bit view on the registry. The purpose of this option is mainly for symmetry. It permits creation of OS agnostic scripts which would also work in a hypothetical 64 bit version of Cygwin. You must provide regtool with an action following options (if any). Currently, the action must be add, set, check, get, list, remove, set, or unset. The add action adds a new key. The check action checks to see if a key exists (the exit code of the program is zero if it does, nonzero if it does not). The get action gets the value of a key, and prints it (and nothing else) to stdout. Note: if the value doesn't exist, an error message is printed and the program returns a non-zero exit code. If you give -q, it doesn't print the message but does return the non-zero exit code. The list action lists the subkeys and values belonging to the given key. With list, the -k option instructs regtool to print only KEYs, and the -l option to print only VALUEs. The -p option postfixes a '/' to each KEY, but leave VALUEs with no postfix. The remove action removes a key. Note that you may need to remove everything in the key before you may remove it, but don't rely on this stopping you from accidentally removing too much. The get action prints a value within a key. With the -b option, data is printed as hex bytes. -n allows to print the data as a typeless stream of bytes. Integer values (REG_DWORD, REG_QWORD) are usually printed as decimal values. The -x option allows to print the numbers as hexadecimal values. The set action sets a value within a key. -b means it's binary data (REG_BINARY). The binary values are specified as hex bytes in the argument list. If the argument is '-', binary data is read from stdin instead. -d or -i means the value is a 32 bit integer value (REG_DWORD). -D means the value is a 32 bit integer value in Big Endian representation (REG_DWORD_BIG_ENDIAN). -Q means the value is a 64 bit integer value (REG_QWORD). -s means the value is a string (REG_SZ). -e means it's an expanding string (REG_EXPAND_SZ) that contains embedded environment variables. -m means it's a multi-string (REG_MULTI_SZ). If you don't specify one of these, regtool tries to guess the type based on the value you give. If it looks like a number, it's a DWORD, unless it's value doesn't fit into 32 bit, in which case it's a QWORD. If it starts with a percent, it's an expanding string. If you give multiple values, it's a multi-string. Else, it's a regular string. The unset action removes a value from a key. The load action adds a new subkey and loads the contents of a registry hive into it. The parent key must be HKEY_LOCAL_MACHINE or HKEY_USERS. The unload action unloads the file and removes the subkey. The save action saves a subkey into a registry file. Ideally you append the suffix .reg to the file so it gets automatically recognized as registry file by Windows Explorer. The restore action restores a registry subkey from a file saved via the aforementioned save action. By default, the last "\" or "/" is assumed to be the separator between the key and the value. You can use the -K option to provide an alternate key/value separator character. ### setfacl Usage: setfacl [-r] {-f ACL_FILE | -s acl_entries} FILE... setfacl [-r] {-b|[-d acl_entries] [-m acl_entries]} FILE... Modify file and directory access control lists (ACLs) -b, --remove-all remove all extended ACL entries -d, --delete delete one or more specified ACL entries -f, --file set ACL entries for FILE to ACL entries read from a ACL_FILE -k, --remove-default remove all default ACL entries -m, --modify modify one or more specified ACL entries -r, --replace replace mask entry with maximum permissions needed for the file group class -s, --substitute substitute specified ACL entries for the ACL of FILE -h, --help output usage information and exit -V, --version output version information and exit At least one of (-b, -d, -f, -k, -m, -s) must be specified  For each file given as parameter, setfacl will either replace its complete ACL (-s, -f), or it will add, modify, or delete ACL entries. For more information on Cygwin and Windows ACLs, see see the section called “POSIX accounts, permission, and security” in the Cygwin User's Guide. Acl_entries are one or more comma-separated ACL entries from the following list:  u[ser]::perm u[ser]:uid:perm g[roup]::perm g[roup]:gid:perm m[ask]::perm o[ther]::perm  Default entries are like the above with the additional default identifier. For example:  d[efault]:u[ser]:uid:perm  perm is either a 3-char permissions string in the form "rwx" with the character '-' for no permission or it is the octal representation of the permissions, a value from 0 (equivalent to "---") to 7 ("rwx"). uid is a user name or a numerical uid. gid is a group name or a numerical gid. The following options are supported: -b Remove all extended ACL entries. The base ACL entries of the owner, group and others are retained. -d Delete one or more specified entries from the file's ACL. The owner, group and others entries must not be deleted. Acl_entries to be deleted should be specified without permissions, as in the following list:  u[ser]:uid[:] g[roup]:gid[:] m[ask][:] d[efault]:u[ser][:uid] d[efault]:g[roup][:gid] d[efault]:m[ask][:] d[efault]:o[ther][:]  -f Take the Acl_entries from ACL_FILE one per line. Whitespace characters are ignored, and the character "#" may be used to start a comment. The special filename "-" indicates reading from stdin. Note that you can use this with getfacl and setfacl to copy ACLs from one file to another: $ getfacl source_file | setfacl -f - target_file


Required entries are: one user entry for the owner of the file, one group entry for the group of the file, and one other entry.

If additional user and group entries are given: a mask entry for the file group class of the file, and no duplicate user or group entries with the same uid/gid.

If it is a directory: one default user entry for the owner of the file, one default group entry for the group of the file, one default mask entry for the file group class, and one default other entry.

-k Remove all default ACL entries. If no default ACL entries exist, no warnings are issued.

-m Add or modify one or more specified ACL entries. Acl_entries is a comma-separated list of entries from the same list as above.

-r Causes the permissions specified in the mask entry to be ignored and replaced by the maximum permissions needed for the file group class.

-s Like -f, but substitute the file's ACL with Acl_entries specified in a comma-separated list on the command line.

While the -d and -m options may be used in the same command, the -f and -s options may be used only exclusively.

Directories may contain default ACL entries. Files created in a directory that contains default ACL entries will have permissions according to the combination of the current umask, the explicit permissions requested and the default ACL entries

### setmetamode

Usage: setmetamode [metabit|escprefix]

Get or set keyboard meta mode

Without argument, it shows the current meta key mode.
metabit|meta|bit     The meta key sets the top bit of the character.
escprefix|esc|prefix The meta key sends an escape prefix.

Other options:

-h, --help           This text
-V, --version        Print program version and exit


setmetamode can be used to determine and set the key code sent by the meta (aka Alt) key.

### ssp

Usage: ssp [options] low_pc high_pc command...

Single-step profile COMMAND

-c, --console-trace  trace every EIP value to the console. *Lots* slower.
-d, --disable        disable single-stepping by default; use
OutputDebugString ("ssp on") to enable stepping
-e, --enable         enable single-stepping by default; use
OutputDebugString ("ssp off") to disable stepping
-h, --help           output usage information and exit
-l, --dll            enable dll profiling.  A chart of relative DLL usage
is produced after the run.
race conditions.
-t, --trace-eip      trace every EIP value to a file TRACE.SSP.  This
gets big *fast*.
-v, --verbose        output verbose messages about debug events.
-V, --version        output version information and exit

Example: ssp 0x401000 0x403000 hello.exe


SSP - The Single Step Profiler

Original Author: DJ Delorie

The SSP is a program that uses the Win32 debug API to run a program one ASM instruction at a time. It records the location of each instruction used, how many times that instruction is used, and all function calls. The results are saved in a format that is usable by the profiling program gprof, although gprof will claim the values are seconds, they really are instruction counts. More on that later.

Because the SSP was originally designed to profile the Cygwin DLL, it does not automatically select a block of code to report statistics on. You must specify the range of memory addresses to keep track of manually, but it's not hard to figure out what to specify. Use the "objdump" program to determine the bounds of the target's ".text" section. Let's say we're profiling cygwin1.dll. Make sure you've built it with debug symbols (else gprof won't run) and run objdump like this:

$objdump -h cygwin1.dll  It will print a report like this: cygwin1.dll: file format pei-i386 Sections: Idx Name Size VMA LMA File off Algn 0 .text 0007ea00 61001000 61001000 00000400 2**2 CONTENTS, ALLOC, LOAD, READONLY, CODE, DATA 1 .data 00008000 61080000 61080000 0007ee00 2**2 CONTENTS, ALLOC, LOAD, DATA . . .  The only information we're concerned with are the VMA of the .text section and the VMA of the section after it (sections are usually contiguous; you can also add the Size to the VMA to get the end address). In this case, the VMA is 0x61001000 and the ending address is either 0x61080000 (start of .data method) or 0x0x6107fa00 (VMA+Size method). There are two basic ways to use SSP - either profiling a whole program, or selectively profiling parts of the program. To profile a whole program, just run ssp without options. By default, it will step the whole program. Here's a simple example, using the numbers above: $ ssp 0x61001000 0x61080000 hello.exe


This will step the whole program. It will take at least 8 minutes on a PII/300 (yes, really). When it's done, it will create a file called "gmon.out". You can turn this data file into a readable report with gprof:

$gprof -b cygwin1.dll  The "-b" means 'skip the help pages'. You can omit this until you're familiar with the report layout. The gprof documentation explains a lot about this report, but ssp changes a few things. For example, the first part of the report reports the amount of time spent in each function, like this: Each sample counts as 0.01 seconds. % cumulative self self total time seconds seconds calls ms/call ms/call name 10.02 231.22 72.43 46 1574.57 1574.57 strcspn 7.95 288.70 57.48 130 442.15 442.15 strncasematch  The "seconds" columns are really CPU opcodes, 1/100 second per opcode. So, "231.22" above means 23,122 opcodes. The ms/call values are 10x too big; 1574.57 means 157.457 opcodes per call. Similar adjustments need to be made for the "self" and "children" columns in the second part of the report. OK, so now we've got a huge report that took a long time to generate, and we've identified a spot we want to work on optimizing. Let's say it's the time() function. We can use SSP to selectively profile this function by using OutputDebugString() to control SSP from within the program. Here's a sample program:  #include <windows.h> main() { time_t t; OutputDebugString("ssp on"); time(&t); OutputDebugString("ssp off"); }  Then, add the -d option to ssp to default to *disabling* profiling. The program will run at full speed until the first OutputDebugString, then step until the second. You can then use gprof (as usual) to see the performance profile for just that portion of the program's execution. There are many options to ssp. Since step-profiling makes your program run about 1,000 times slower than normal, it's best to understand all the options so that you can narrow down the parts of your program you need to single-step. -v - verbose. This prints messages about threads starting and stopping, OutputDebugString calls, DLLs loading, etc. -t and -c - tracing. With -t, *every* step's address is written to the file "trace.ssp". This can be used to help debug functions, since it can trace multiple threads. Clever use of scripts can match addresses with disassembled opcodes if needed. Warning: creates *huge* files, very quickly. -c prints each address to the console, useful for debugging key chunks of assembler. Use addr2line -C -f -s -e foo.exe < trace.ssp > lines.ssp and then perl cvttrace to convert to symbolic traces. -s - subthreads. Usually, you only need to trace the main thread, but sometimes you need to trace all threads, so this enables that. It's also needed when you want to profile a function that only a subthread calls. However, using OutputDebugString automatically enables profiling on the thread that called it, not the main thread. -l - dll profiling. Generates a pretty table of how much time was spent in each dll the program used. No sense optimizing a function in your program if most of the time is spent in the DLL. I usually use the -v, -s, and -l options: $ ssp -v -s -l -d 0x61001000 0x61080000 hello.exe


### strace

Usage: strace.exe [OPTIONS] <command-line>
Usage: strace.exe [OPTIONS] -p <pid>

Trace system calls and signals

-b, --buffer-size=SIZE       set size of output file buffer
-d, --no-delta               don't display the delta-t microsecond timestamp
-f, --trace-children         trace child processes (toggle - default true)
-h, --help                   output usage information and exit
-n, --crack-error-numbers    output descriptive text instead of error
numbers for Windows errors
-o, --output=FILENAME        set output file to FILENAME
-p, --pid=n                  attach to executing program with cygwin pid n
-q, --quiet                  toggle "quiet" flag.  Defaults to on if "-p",
off otherwise.
-S, --flush-period=PERIOD    flush buffered strace output every PERIOD secs
-t, --timestamp              use an absolute hh:mm:ss timestamp insted of
the default microsecond timestamp.  Implies -d
-T, --toggle                 toggle tracing in a process already being
traced. Requires -p <pid>
-u, --usecs                  toggle printing of microseconds timestamp
-V, --version                output version information and exit
-w, --new-window             spawn program under test in a new window

MASK can be any combination of the following mnemonics and/or hex values
(0x is optional).  Combine masks with '+' or ',' like so:

Mnemonic Hex     Corresponding Def  Description
=========================================================================
all      0x000001 (_STRACE_ALL)      All strace messages.
flush    0x000002 (_STRACE_FLUSH)    Flush output buffer after each message.
inherit  0x000004 (_STRACE_INHERIT)  Children inherit mask from parent.
uhoh     0x000008 (_STRACE_UHOH)     Unusual or weird phenomenon.
syscall  0x000010 (_STRACE_SYSCALL)  System calls.
startup  0x000020 (_STRACE_STARTUP)  argc/envp printout at startup.
debug    0x000040 (_STRACE_DEBUG)    Info to help debugging.
paranoid 0x000080 (_STRACE_PARANOID) Paranoid info.
termios  0x000100 (_STRACE_TERMIOS)  Info for debugging termios stuff.
select   0x000200 (_STRACE_SELECT)   Info on ugly select internals.
wm       0x000400 (_STRACE_WM)       Trace Windows msgs (enable _strace_wm).
sigp     0x000800 (_STRACE_SIGP)     Trace signal and process handling.
minimal  0x001000 (_STRACE_MINIMAL)  Very minimal strace output.
exitdump 0x004000 (_STRACE_EXITDUMP) Dump strace cache on exit.
system   0x008000 (_STRACE_SYSTEM)   Serious error; goes to console and log.
nomutex  0x010000 (_STRACE_NOMUTEX)  Don't use mutex for synchronization.
malloc   0x020000 (_STRACE_MALLOC)   Trace malloc calls.
special  0x100000 (_STRACE_SPECIAL)  Special debugging printfs for
non-checked-in code


The strace program executes a program, and optionally the children of the program, reporting any Cygwin DLL output from the program(s) to stdout, or to a file with the -o option. With the -w option, you can start an strace session in a new window, for example:

$strace -o tracing_output -w sh -c 'while true; do echo "tracing..."; done' &  This is particularly useful for strace sessions that take a long time to complete. Note that strace is a standalone Windows program and so does not rely on the Cygwin DLL itself (you can verify this with cygcheck). As a result it does not understand symlinks. This program is mainly useful for debugging the Cygwin DLL itself. ### tzset Usage: tzset [OPTION] Print POSIX-compatible timezone ID from current Windows timezone setting Options: -h, --help output usage information and exit. -V, --version output version information and exit. Use tzset to set your TZ variable. In POSIX-compatible shells like bash, dash, mksh, or zsh: export TZ=$(tzset)

In csh-compatible shells like tcsh:

setenv TZ tzset


The tzset tool reads the current timezone from Windows and generates a POSIX-compatible timezone information for the TZ environment variable from that information. That's all there is to it. For the way how to use it, see the above usage information.

### umount

Usage: umount.exe [OPTION] [<posixpath>]

Unmount filesystems

-h, --help                    output usage information and exit
-U, --remove-user-mounts      remove all user mounts
-V, --version                 output version information and exit


The umount program removes mounts from the mount table in the current session. If you specify a POSIX path that corresponds to a current mount point, umount will remove it from the current mount table. Note that you can only remove user mount points. The -U flag may be used to specify removing all user mount points from the current user session.

See the section called “The Cygwin Mount Table” for more information on the mount table.