In Unix, what do some obscurely named commands stand for?
A list of some of the more obscurely named Unix commands follows:
- Aho, Weinberger, and Kernighan
The awk scripting language was named by its authors, Al Aho, Peter Weinberger, and Brian Kernighan. For more, see What is awk, and how do I use it?
- Global regular expression print
The grep command comes from the command used by the
edprogram (a simple and venerable Unix text editor) to print all lines matching a certain pattern: g/re/p For more, see What is grep, and how do I use it?
- Fixed grep
fgrepcommand searches for fixed strings only, possibly taking the strings from another file. The "f" does not stand for "fast"; in fact, at times, using the
fgrepcommand can be slower than using the
egrepcommand. However, the
fgrepcommand may still be useful when searching a file for a larger number of strings than the
egrepcommand can handle.
- Extended grep
egrepcommand uses fancier regular expressions than the
grepcommand. Many people use the
egrepcommand for its internal algorithms, which are more sophisticated than the
fgrepcommands. Also, the
egrepcommand is usually the fastest of the three programs.
"Catenate" is an obscure word meaning "to connect in a series", which is what the
catcommand does to one or more files. This is not to be confused with C/A/T, the Computer Aided Typesetter. For more, see In Unix, how do I combine several text files into a single file?
- New roff, Typesetter new roff
These two commands are descendants of the
roffcommand, which was a re-implementation of the Multics
runoffprogram would "run off" a good copy of a document.
teecommand is named after plumbing terminology for a T-shaped pipe splitter. This Unix command splits the output of another command, sending it to a file and to the terminal.
- A dog named Biff
This command, which turns on asynchronous mail notification, was actually named after a dog. Courtesy of Eric Cooper, Carnegie Mellon University:
"I can confirm the origin of
biff, if you're interested. Biff was Heidi Stettner's dog, back when Heidi (and I, and Bill Joy) were all grad students at U.C. Berkeley and the early versions of BSD were being developed. Biff was popular among the residents of Evans Hall, and was known for barking at the mailman, hence the name of the command."
- runcom (as in
rccommand derives from the
runcomfacility from the MIT CTSS system, ca. 1965. From Brian Kernighan and Dennis Ritchie, as told to Vicki Brown:
Note: The name of the shell from the Plan 9 operating system is also
"There was a facility that would execute a bunch of commands stored in a file; it was called
runcomfor "run commands", and the file began to be called "a runcom".
rcin Unix is a fossil from that usage."
- Practical extraction and report language
The Perl language is a text, process, and file manipulation tool, created by Larry Wall. Perl bridges the gap between shell and C programming, and is free and completely portable. The acronym is one of many variants proposed, with varying degrees of seriousness, as the true origin of the name. However, this is currently regarded as apocryphal. Spelling Perl as "PERL", as though it is an acronym, is incorrect. For further information, see the Usenet newsgroup
comp.lang.perland the Perl FAQ.
For more interesting tidbits, see the book Life with Unix by Don Libes.
At Indiana University, for personal or departmental Linux or Unix systems support, see At IU, how do I get support for Linux or Unix?
Last modified on June 07, 2012.