GNU Core Utilities
Coreutils is a package of GNU software containing many of the basic tools such as cat, ls, and rm needed for Unix-like operating systems to function. It is a combination of a number of earlier packages, including textutils, shellutils, and fileutils along with some other miscellaneous utilties.
The GNU core utilities support long options as parameters to the commands, and the "--help" option is also available to provide some fairly verbose information about what the program is, and how it is to be used. This is in contrast to more traditional Unix operating systems, which generally don't support long options, and usually only have very terse help screens (if they exist at all).
For instance, if a user doesn't know how to use the cat program on a Linux machine, that person could just type in "cat --help" and get idea of what the program does.
[mike@3po][~]$ cat --help
Usage: cat [OPTION] [FILE]...
Concatenate FILE(s), or standard input, to standard output.
-A, --show-all equivalent to -vET
-b, --number-nonblank number nonblank output lines
-e equivalent to -vE
-E, --show-ends display $ at end of each line
-n, --number number all output lines
-r, --reversible use \ to make the output reversible, implies -v
-s, --squeeze-blank never more than one single blank line
-t equivalent to -vT
-T, --show-tabs display TAB characters as ^I
-u (ignored)
-v, --show-nonprinting use ^ and M- notation, except for LFD and TAB
--help display this help and exit
--version output version information and exit
With no FILE, or when FILE is -, read standard input.
Report bugs to <bug-coreutils@gnu.org>.
In contrast, the cat program on a Solaris 8 machine does not produce very useful information.
hick0088@garnet ~>$ cat --help cat: illegal option -- - usage: cat [ -usvtebn ] [-|file] ...
The Debian coreutils-5.2.1-2 package (a slightly modified version of coreutils version 5.2.1) contains these programs:
basename, cat, chgrp, chmod, chown, chroot, cksum, comm, cp, csplit, cut, date, dd, df, dir, dircolors, dirname, du, echo, env, expand, expr, factor, false, fmt, fold, groups, head, hostid, id, install, join, link, ln, logname, ls, md5sum, mkdir, mkfifo, mknod, mv, nice, nl, nohup, od, paste, pathchk, pinky, pr, printenv, printf, ptx, pwd, readlink, rm, rmdir, sha1sum, seq, shred, sleep, sort, split, stat, stty, sum, sync, tac, tail, tee, test, touch, tr, true, tsort, tty, uname, unexpand, uniq, unlink, users, vdir, wc, who, whoami, yes