@ifinfo
@format
START-INFO-DIR-ENTRY
-* Shell utilities: (sh-utils). GNU shell utilities.
-* basename invocation: (sh-utils)basename invocation.
- Strip directory and suffix from a file name.
-* date invocation: (sh-utils)date invocation.
- Print or set system date and time.
-* dirname invocation: (sh-utils)dirname invocation.
- Strip non-directory suffix from a file name.
-* echo invocation: (sh-utils)echo invocation.
- Print a line of text.
-* env invocation: (sh-utils)env invocation.
- Modify the environment.
-* expr invocation: (sh-utils)expr invocation.
- Evaluate expressions.
-* false invocation: (sh-utils)false invocation.
- Do nothing, unsuccessfully.
-* groups invocation: (sh-utils)groups invocation.
- Print group names a user is in.
-* hostname invocation: (sh-utils)hostname invocation.
- Print or set system name.
-* id invocation: (sh-utils)id invocation.
- Print real and effective uid and gid.
-* logname invocation: (sh-utils)logname invocation.
- Print current login name.
-* nice invocation: (sh-utils)nice invocation.
- Modify the scheduling priority.
-* pathchk invocation: (sh-utils)pathchk invocation.
- Check file name portability.
-* printenv invocation: (sh-utils)printenv invocation.
- Print all or part of the environment.
-* printf invocation: (sh-utils)printf invocation.
- Format and print data.
-* pwd invocation: (sh-utils)pwd invocation.
- Print working directory.
-* sleep invocation: (sh-utils)sleep invocation.
- Delay for a specified time.
-* stty invocation: (sh-utils)stty invocation.
- Print or change terminal characteristics.
-* su invocation: (sh-utils)su invocation.
- Modify the user and group id.
-* tee invocation: (sh-utils)tee invocation.
- Redirect output to multiple files.
-* test invocation: (sh-utils)test invocation.
- Check file types and compare values.
-* true invocation: (sh-utils)true invocation.
- Do nothing, successfully.
-* tty invocation: (sh-utils)tty invocation.
- Print or change terminal characteristics.
-* uname invocation: (sh-utils)uname invocation.
- Print system information.
-* users invocation: (sh-utils)users invocation.
- Print login names of users currently logged in.
-* who invocation: (sh-utils)who invocation.
- Print who is currently logged in.
-* whoami invocation: (sh-utils)whoami invocation.
- Print effective user id.
-* yes invocation: (sh-utils)yes invocation.
- Print a string until interrupted.
+* Shell utilities: (sh-utils). GNU shell utilities.
+* basename: (sh-utils)basename invocation. Strip directory and suffix.
+* date: (sh-utils)date invocation. Print/set system date and time.
+* dirname: (sh-utils)dirname invocation. Strip non-directory suffix.
+* echo: (sh-utils)echo invocation. Print a line of text.
+* env: (sh-utils)env invocation. Modify the environment.
+* expr: (sh-utils)expr invocation. Evaluate expressions.
+* false: (sh-utils)false invocation. Do nothing, unsuccessfully.
+* groups: (sh-utils)groups invocation. Print group names a user is in.
+* hostname: (sh-utils)hostname invocation. Print or set system name.
+* id: (sh-utils)id invocation. Print real/effective uid/gid.
+* logname: (sh-utils)logname invocation. Print current login name.
+* nice: (sh-utils)nice invocation. Modify scheduling priority.
+* pathchk: (sh-utils)pathchk invocation. Check file name portability.
+* printenv: (sh-utils)printenv invocation. Print environment variables.
+* printf: (sh-utils)printf invocation. Format and print data.
+* pwd: (sh-utils)pwd invocation. Print working directory.
+* sleep: (sh-utils)sleep invocation. Delay for a specified time.
+* stty: (sh-utils)stty invocation. Print/change terminal settings.
+* su: (sh-utils)su invocation. Modify user and group id.
+* tee: (sh-utils)tee invocation. Redirect to multiple files.
+* test: (sh-utils)test invocation. File/string tests.
+* true: (sh-utils)true invocation. Do nothing, successfully.
+* tty: (sh-utils)tty invocation. Print terminal name.
+* uname: (sh-utils)uname invocation. Print system information.
+* users: (sh-utils)users invocation. Print current user names.
+* who: (sh-utils)who invocation. Print who is logged in.
+* whoami: (sh-utils)whoami invocation. Print effective user id.
+* yes: (sh-utils)yes invocation. Print a string indefinitely.
END-INFO-DIR-ENTRY
@end format
@end ifinfo
@titlepage
@title GNU sh-utils, version @value{VERSION}
@subtitle A set of shell utilities
-@subtitle for version @value{VERSION}, @value{RELEASE_DATE}
-@author Jim Meyering
+@subtitle for version @value{VERSION}, @value{RELEASE-DATE}
+@author David MacKenzie et al.
@page
@vskip 0pt plus 1filll
@cindex utilities for shell programming
This manual minimally documents version @value{VERSION} of the GNU shell
-utilities. The @code{stty} section, in particular, needs substantial
-reorganization and additional explanatory text before it will be up to
-the standard of other GNU manuals.
-
-@cindex POSIX.2
-The GNU shell utilities are mostly compatible with the POSIX.2 standard.
+utilities. See the introduction for caveats.
@menu
+* Introduction:: Caveats, overview, and author.
* Common options:: Common options.
* Printing text:: echo printf yes
* Conditions:: false true test expr
@end ifinfo
+@node Introduction
+@chapter Introduction
+
+@cindex introduction
+
+First of all, this manual is incomplete. The @code{stty} section, in
+particular, needs substantial reorganization and additional explanatory
+text before it will be up to the standard of other GNU manuals.
+Explanatory text in general is lacking; the manual presently assumes you
+pretty much know what to do, and just need to be reminded of how. Thus,
+if you are interested, please get involved in improving this manual.
+The entire GNU community will benefit.
+
+Some of these programs are useful only when writing shell scripts;
+utilities like these are, in fact, the ``language'' of shell scripts (to
+a great extent). Others are occasionally useful interactively.
+
+@cindex POSIX.2
+The GNU shell utilities are mostly compatible with the POSIX.2 standard.
+
+Please report bugs to @samp{bug-gnu-utils@@prep.ai.mit.edu}. Remember
+to include the version number, machine architecture, input files, and
+any other information needed to reproduce the bug. @xref{Bugs, , , gcc,
+GNU CC}.
+
+This manual is based on the Unix man pages in the distribution, which
+were originally written by David MacKenzie and updated by Jim Meyering.
+Francois Pinard did the initial conversion to Texinfo format. Karl
+Berry did the indexing, some reorganization, and editing of the results.
+Richard Stallman contributed his usual invaluable insights to the
+overall process.
+
+
@node Common options
@chapter Common options
followed by a newline, forever until it is killed. If no arguments are
given, it prints @samp{y} followed by a newline forever until killed.
-The only options are a lone @samp{--help} or
-@samp{--version}. @xref{Common options}.
+The only options are a lone @samp{--help} or @samp{--version}.
+@xref{Common options}.
@node Conditions
@menu
* pwd invocation:: Print working directory.
* stty invocation:: Print or change terminal characteristics.
-* printenv invocation:: Print all or part of the environment.
+* printenv invocation:: Print environment variables.
* tty invocation:: Print file name of terminal on standard input.
@end menu
@node printenv invocation
-@section @code{printenv}: Print all or part of the environment
+@section @code{printenv}: Print all or some environment variables
@pindex printenv
-@cindex printing all or part of the environment
-@cindex environment, printing all or part of
+@cindex printing all or some environment variables
+@cindex environment variables, printing
Synopsis:
printenv [ @var{option} ] [ @var{variable} ]@dots{}
@end example
-If no @var{variable}s are specified, @code{printenv} prints the entire
-environment. Otherwise, it prints the value of each @var{variable} that
-is set, and nothing for those that are not set.
+If no @var{variable}s are specified, @code{printenv} prints the value of
+every environment variable. Otherwise, it prints the value of each
+@var{variable} that is set, and nothing for those that are not set.
-The only options are a lone @samp{--help} or
-@samp{--version}. @xref{Common options}.
+The only options are a lone @samp{--help} or @samp{--version}.
+@xref{Common options}.
@cindex exit status of @code{printenv}
Exit status:
@cindex parsing date strings
@cindex date strings, parsing
@cindex arbitrary date strings, parsing
+@opindex yesterday
+@opindex tomorrow
+@opindex next @var{day}
+@opindex last @var{day}
+@flindex getdate.y
Display the time and date specified in @var{datestr} instead of the
-current time and date. @var{datestr} can be in almost any common format.
+current time and date. @var{datestr} can be in almost any common
+format. It can contain month names, timezones, @samp{am} and @samp{pm},
+@samp{yesterday}, @samp{ago}, @samp{next}, etc. The source file
+@file{getdate.y} implements this parsing for all GNU routines; we need
+precise documentation!
+
+@item -f @var{datefile}
+@itemx --file=@var{datefile}
+@opindex -f
+@opindex --file
+Parse each line in @var{datefile} as with @samp{-d} and display the
+resulting time and date. If @var{datefile} is @samp{-}, use standard
+input. This is useful when you have many dates to process, because the
+system overhead of starting up the @code{date} executable many times can
+be considerable.
@item -s @var{datestr}
@itemx --set=@var{datestr}
@opindex -s
@opindex --set
-Set the time and date to @var{datestr}, which can be in almost any
-common format. It can contain month names, timezones, @samp{am} and
-@samp{pm}, @samp{yesterday}, @samp{ago}, etc.
+Set the time and date to @var{datestr}, See @samp{-d} above.
@item -u
@itemx --utc
@cindex examples of @code{date}
-Here are a few examples.
+Here are a few examples. Also see the documentation for the @samp{-d}
+option in the previous section.
@itemize @bullet
@item
To print the date of the day before yesterday:
+
@example
date --date='2 days ago'
@end example
But this may not be what you want because for the first nine days of
the month, the @samp{%d} expands to a zero-padded two-digit field,
-for example @samp{date -d 1-may '+%B %d'} will print @samp{May 01}.
+for example @samp{date -d 1may '+%B %d'} will print @samp{May 01}.
@item
To print a date without the leading zero for one-digit days
of the month, you can use the (GNU extension) @code{-} modifier to suppress
the padding altogether.
@example
-date -d=1-may '+%B %-d'
+date -d=1may '+%B %-d'
@end example
@item
To print the current date and time in the format required by many
non-GNU versions of @code{date} when setting the system clock:
@example
-date +%m%d%H%M%Y.%s
+date +%m%d%H%M%Y.%S
@end example
@item
user, etc.
@menu
-* env invocation:: Modify the environment.
-* nice invocation:: Modify the scheduling priority.
+* env invocation:: Modify environment variables.
+* nice invocation:: Modify scheduling priority.
* nohup invocation:: Immunize to hangups.
-* su invocation:: Modify the user and group id.
+* su invocation:: Modify user and group id.
@end menu
@node env invocation
-@section @code{env}: Run a program in a modified environment
+@section @code{env}: Run a command in a modified environment
@pindex env
@cindex environment, running a program in a modified
@node nice invocation
-@section @code{nice}: Run a program with modified scheduling priority
+@section @code{nice}: Run a command with modified scheduling priority
@pindex nice
@cindex modifying scheduling priority
@node nohup invocation
-@section @code{nohup}: Run a program immune to hangups
+@section @code{nohup}: Run a command immune to hangups
@pindex nohup
@cindex hangups, immunity to
@node su invocation
-@section @code{su}: Run a shell with substitute user and group id
+@section @code{su}: Run a command with substitute user and group id
@pindex su
@cindex substitute user and group IDs
the super-user, sets @code{USER} and @code{LOGNAME} to @var{user}.
By default, the shell is not a login shell.
-If one or more @var{arg}s are given, they are passed as additional
-arguments to the shell.
+Any additional @var{arg}s are passed as additional arguments to the
+shell.
@cindex @samp{-su}
-@code{su} does not handle @file{/bin/sh} or any other shells specially
+GNU @code{su} does not treat @file{/bin/sh} or any other shells specially
(e.g., by setting @code{argv[0]} to @samp{-su}, passing @code{-c} only
to certain shells, etc.).
@findex syslog
-On systems that have @code{syslog}, @code{su} can be compiled to report
-failed, and optionally successful, @code{su} attempts using
-@code{syslog}.
-
-@cindex wheel group, not supported
-@cindex group wheel, not supported
-@cindex fascism
-This program does not support a ``wheel group'' that restricts who
-can @code{su} to super-user accounts, because that can help fascist
-system administrators hold unwarranted power over other users.
+@code{su} can optionally be compiled to use @code{syslog} to report
+failed, and optionally successful, @code{su} attempts. (If the system
+supports @code{syslog}.) However, GNU @code{su} does not check if the
+user is a member of the @code{wheel} group; see below.
The program accepts the following options. Also see @ref{Common options}.
@end table
+@cindex wheel group, not supported
+@cindex group wheel, not supported
+@cindex fascism
+@heading Why GNU @code{su} does not support the @samp{wheel} group
+
+(This section is by Richard Stallman.)
+
+@cindex Twenex
+@cindex MIT AI lab
+Sometimes a few of the users try to hold total power over all the
+rest. For example, in 1984, a few users at the MIT AI lab decided to
+seize power by changing the operator password on the Twenex system and
+keeping it secret from everyone else. (I was able to thwart this coup
+and give power back to the users by patching the kernel, but I
+wouldn't know how to do that in Unix.)
+
+However, occasionally the rulers do tell someone. Under the usual
+@code{su} mechanism, once someone learns the root password who
+sympathizes with the ordinary users, he or she can tell the rest. The
+``wheel group'' feature would make this impossible, and thus cement the
+power of the rulers.
+
+I'm on the side of the masses, not that of the rulers. If you are
+used to supporting the bosses and sysadmins in whatever they do, you
+might find this idea strange at first.
+
@node Delaying
@chapter Delaying
projects / thirdparty / coreutils.git / commitdiff
