What do Unix command names stand for? | Hacker News Reader

What do Unix command names stand for?

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362 pointsPete_D153 comments

David F. here, with the best true Unix command-name story ever: In the late 1980's, Frame Technology had 50 or 100 employees, and as our product ran on Sun 3/50 workstations, not only the engineers, but many of the admins had them; and of course they all ran the SunOS version of Unix.

One day, Laurie S. from the business side came over to ask me for some help with her system: "I think I've filled up my disk, but how can I find out?" "Well, the 'df' command will show you that info." "But," she replied, "won't that just show me the files in your home directory?" "My home directory??? Why would it do that?" "Well, my initials are LS and that shows my files, and DF are your initials, so that should show your files."

I was super impressed.

At Sun there was a salesperson, formerly of DEC, who had been taught, in DEC salestraining, that PDP (as in PDP-11/70) stood for “Pink and Dark Purple”, so they could recognize their machines in the lab.

I'm glad nobody taught me that.

Sometimes it only works with a trailing slash.

The one major thing I really like about the terseness of these commands is that, although they have a steeper learning curve at first, once you learn them --- which happens quickly with repeated use --- they feel very natural and you use them almost as if they're an extension of English, like a special dialect; talking with coworkers, we use words like "cat", "grep", "ls", "sudo", etc. as verbs.

Contrast this with the verbosity of more "modern" command languages like Powershell: while those may be a bit easier to understand the very first time, every time thereafter it feels like you're talking in a language where every word is a minimum of 10 letters and two syllables long. The mental overhead is far higher.

I've always remembered "bss" as the "bull-shit segment" --- because it initially doesn't have any useful content.

The commands you list aren't too bad because they get quickly learned through use. And "grep" at least is pronounceable and feels strangely apt as a command name.

In general though I think the terseness of the standard Unix commands is a problem, particularly for less often used commands. Even after many years of using them I still get "du" and "df" confused, for example.

But how.. du = disk usage, df = disk free...

"Disk usage" could plausibly be the command that tells you how much space you've got left. Maybe "disk free" doesn't apply quite as well to du's function.

If I was designing them from scratch, I'd maybe call them something like "size" and "space" respectively.

> "Disk usage" could plausibly be the command that tells you how much space you've got left.

"Red touches yellow, you're an okay fellow. Red touches black, you're a dead jack"

It's a good thing there aren't any coral snakes around where I live.

I learned Unix in the mid 80s but it wasn't until sometime later I learned or had the epiphany that grep was shorthand for g/re/p. As in global search for regular expression and print the results. Talk about a forehead slapping moment. Not everything in Unix is immediately obvious.

The way I remember du and df is Disk Usage and Display (mounted) Filesystems, respectively.

I always remember them as "disk usage" and "disk free".

I always end up using both du and df because I can never remember which does what. Half the time, I also can’t remember their names even and have to look them up.

All of the really frequent commands, I can remember (cp, mv, cat, tar, head, tail, ls, mkdir, rm, grep, sed, and a handful of common programs like package managers and git) and everything else I can never remember and have to look up. I personally don’t like the unix command names, most don’t make much sense to me personally. Sure, I like that they’re short, but I can never remember them unless I use them a lot.

Tab completion to the rescue! Once you're a few letters past the dash in Powershell, you can just hot the tab key until you've cycled through the few commands it spells. Same for parameters.

Doesn't help that a lot of commands have the same prefix 'Get-' / 'Set-', 'Add-', etc, so you have to type at least 6 characters, including a '-', to get useful completion.

Powershell has aliases, so you can use 'ls' instead of 'Get-ChildItem'. My colleagues tend to use Get-ChildItem in scripts and ls when typing at the command prompt.

Personally, I prefer 'ls' for scripts too. I would never use "rd" for a variable name, but since I speak Unix, the more concise 'ls' seems better. To my colleagues without a Unix background, Get-ChildItem, probably is a better choice.

These are the approved verbs. Powershell function names have to be in "verb-noun" format, forcing a level of standardization on the language. It seems like an odd idea to me.

https://msdn.microsoft.com/en-us/library/ms714428(v=vs.85).a...

My favorite: "dd" the "copy and convert" command, but "cc" was already taken by the C compiler.

Ever since somebody told me the joke, I can't help thinking of it as "disk destroyer". It's a much more appropriate name.

Yep learned my lesson once on a malformed dd command and never again have I made a mistake.

Reminds me of “rm -Rf” meaning “read mail really fast” ;)

Hah, a BOFH reference :-)

I thought it came from JCL's DD (Data Definition) statement. Even the parameter syntax is somewhat reminiscent of JCL's DD, while being completely alien to normal Unix commands.

It is. It was making fun of the IBM command.

The dd-style syntax isn't actually that bad. of=X if=Y is possibly easier to remember than -o X -i Y, while still being less typing that --output X --input Y.

JCL itself has a lot of warts, no denying that. But the basic idea behind the DD statement is interesting. In Unix, file descriptors are just numbers; whereas, in classic MVS, instead of numeric file descriptors the API uses 1-8 character names (DDNAMEs). While in principle a Unix program can inherit any number of file descriptors, in practice very few programs inherit any more than 0-2, because remembering numbers has poor usability. In classic MVS, it is not uncommon for a program to inherit more than 3 file descriptors, because they are assigned names not numbers. ("File descriptors" and "inherit" are not quite the right terms, but trying to use Unix-like language to make it comprehensible to people.)

(And I say classic MVS, because contemporary z/OS is actually a conforming Unix implementation so it supports numeric file descriptors in the Unix API, as well as alphanumeric DDNAMEs in the classic MVS API.)

My favorite, related, piece of trivia about JCL is the IEFBR14 program: the no-op program that took a few attempts to get it right :-) [1]. Its entire purpose was motivated by JCL not having primary commands to do file management, which is only allowed as a "side effect" of executing a program

[1] https://en.wikipedia.org/wiki/IEFBR14#Implementation

>> JCL itself has a lot of warts, no denying that.

Unix Programmer: "Huh? Why did you comment out the entire program, except for that one function?"

Mainframe Programmer: What? No, those are JCL statement lines."

Unix Programmer: "..."

I'm not sure it is fair to call that a wart. Back when JCL was designed, C/C++ didn't exist yet, and nobody used "//" as a comment syntax. (C's predecessor BCPL introduced // comments, but it was designed in 1967, and OS/360 was already shipping to customers in 1966; C itself was designed in 1972, and initially it didn't have // comments; C++ borrowed them from BCPL in the 1980s, and then C borrowed them back from C++ after that.)

A more obvious example of a wart would be how it exposes low-level details of disk layout (e.g. space allocation in cylinders and tracks), which improved performance and simplified implementation back in the 1960s, but which nowadays is just useless complexity–modern disks have completely different physical layout, and you have to buy expensive mainframe-specific SAN controllers which know how to simulate the ECKD physical layout of legacy mainframe disks on top of modern industry standard disks/SSDs.

I agree that this is just a "wart" from the perspective of a modern programmer, faced for the first time with JCL (and mainframes in general).

I guess this happens less often otherwse there would be many more of this kind of joke.

I still think that unless you are very proficient on it, having to look at the manual every time you use dd is a good thing.

Which is funny on a different note because ibm had the deskstar hard drives better known as the deathstar drive

I'm pretty sure that was coined specifically in reference to the Deskstar 75GXP series, not Deskstar drives in general. The Deskstar brand name is actually still used by HGST for its NAS drives, which seem to be reasonably well-regarded for their intended applications.

I still pause to remember that I have to type 'if=' and 'of=' and 'bs=' instead of just remembering the order of arguments.

What always gets me is ssh, scp and sftp... having to specify oPort= for sftp compared to -p for ssh.

You can use -P.

Whoever made it -p in ssh & -P in scp can fuck right off.

The reason is that scp was designed as a secure replacement for rcp, which was designed as a remote version of cp. The flags -p and -r were inherited from cp by rcp (see https://linux.die.net/man/1/rcp), so for compatibility scp had to use the same flags.

As for ssh, I haven't looked at its history, but I suspect it's older than scp; the intuitive flag for "port" is -p, so that's what ssh used.

Good to know. I wonder if that's a recent improvement? Last time I was doing lots of sysadmin work was 2011.

I'd prefer ddrescue or just pv, just for the progress meter, and saner arguments.

`tldr`[0] can be helpful for quick references like this. I never worry about commands like `ssh` anymore because of this. This is the output for `dd`:

$ tldr dd

Convert and copy a file.

- Make a bootable usb drive from an isohybrid file (such like archlinux-xxx .iso):

    dd if=file.iso of=/dev/usb_drive

- Clone a drive to another drive with 4MB block and ignore error:

    dd if=/dev/source_drive of=/dev/dest_drive bs=4m conv=noerror

- Generate a file of 100 random bytes by using kernel random driver:

    dd if=/dev/urandom of=random_file bs=100 count=1

- Benchmark the write performance of a disk:

    dd if=/dev/zero of=file_1GB bs=1024 count=1000000

[0]: https://github.com/tldr-pages/tldr

I've been using a similar command called 'cheat' [pip install cheat] which does more or less the same thing. I wonder which of the two is more comprehensive. How would I check this efficiently?

I always thought it was "data dump".

I thought it was "data director".

Later backronymed to "disk destroyer", of course.

Ahh. I had it as "Device Direct (Copy)" for some reason.

I, for some reason, have it as 'disk duplicate' in my mind.

I've always thought of it as "data dump"

> nroff = "New ROFF" > These are descendants of "roff", which was a re-implementation of the Multics "runoff"

Wouldn’t it have been cool if nroff was “nuroff” so that run was spelled backwards, and “new” was represented phonetically?

Kristaps Dzonsons released a great and well researched history of roff derivatives and manpages in general: https://manpages.bsd.lv/history.html

troff -m specifies which macro package to use and the system docs are written with the "an" macro set. So you can runoff (pun intended) the manpages using troff -man.

I once asked Gumby if he and John Gilmore and Michael Tiemann named their company "Cygnus" as the result of typing "grep gnu /usr/dict/words". Without missing a beat, he replied that if they'd thought of doing that, they would have named the company "Wingnut".

> cat = "CATenate" > catenate is an obscure word

The word is concatenate.

dd isn't on there, but it's good: it stands for 'copy and convert'. As you can imagine 'cc' was taken.

'less' is a joke, people who remember 'more' might find it funny, but few people remember 'more' so younger folks just think it's a nonsense name.

> The word is concatenate.

Catenate is a valid word, and synonymous with concatenate. Plus, "cat" makes a better 3 letter unix program name than "con", right?

https://en.wiktionary.org/wiki/catenate

https://en.wikipedia.org/wiki/Catenation

Googling the difference (hint: none) I found this lovely ditty:

I never concatenate strings; I just catenate those little things. Of syllables few, I'm a man through and through. Shorter words? My heart joyfully sings!

David Gries

http://www.cs.cornell.edu/courses/JavaAndDS/files/catenate.p...

Not only that but the v7 man page actually uses the word catenate in the synopsis.

    cat - catenate and print

https://www.unix.com/man-page/v7/1/cat/

Non-mobile links:

https://en.wiktionary.org/wiki/catenate

https://en.wikipedia.org/wiki/Catenation

Thanks. I've edited & updated my links.

> 'less' is a joke, people who remember 'more' might find it funny, but few people remember 'more' so younger folks just think it's a nonsense name.

Carrying on the trend, there's also 'most'. https://en.wikipedia.org/wiki/Most_(Unix)

On some systems more is synlinked to less; so less isn't more, but more is less!

Less makes sense to me. When a command spits out too much text to fit on your screen, you pipe it to less to show you less at once.

Fair enough, but more also made sense to me because I assumed (apparently rightly) that its name refers to the "-- More --" prompt at the end of each screenful.

No. The command would be called called fewer (e.g., show me fewer lines) if that was the case.

The Danish word for “read” is “læs”, which is close to less in pronounciation, so in a way it makes sense to us.

less is more.

  less

is an improved version of

  more

Hence, the joke.

Huh. I suppose it makes less sense to the non-danes, then.

More or less.

Windows have always shipped with 'more', so there a lot more people who still remembers it than you thought.

And DOS before it. There's a reason more on Windows is named more.com (despite being a PE).

I know, but most people didn't use the command line daily post Windows 95, and many more people were born after it was released!

My thoughts exactly: https://en.m.wikipedia.org/wiki/Concatenation

Concatenate is the more popular form over catenate, though it's interesting to see that it only started to leap ahead in the 60s and 70s:

https://books.google.com/ngrams/graph?content=Catenate%2C+co...

Crap, I thought "more" was still the default paginator. It's not, at least not in OS X.

'more' still works on OpenBSD, but funnily enough it's just 'less' in disguise.

https://man.openbsd.org/more

more is less

To continue the successor names, we've also got:

bison from yacc (yet another compiler compiler)

pine (pine is not elm) from elm (did that one stand for anything)

You missed flex from lex.

And then:

* getty; agetty ("alternative"); mingetty ("minimal"); mgetty (I always think "modem" myself); uugetty ("UUCP"); fgetty ("fast"); and ngetty (probably "Nikola")

- https://unix.stackexchange.com/a/316279/5132

* ex; vi; stevie; elvis; calvin; elwin; javi; lemmy; pvic; trived; vigor; vile; vip; virus; winvi; xvi; vim, view, evim, exim, eview, rvim, rview, gvim, gex, gview, rgvim, rgview, vimdiff, and gvimdiff (VIM); nvi; and nvim (NeoVIM)

- http://www.guckes.net/vi/clones.php3

* pax, a peace treaty in the tar versus cpio argument

In math and physics there is the Pin group which is named because it relates to the Spin group (named after spin like of an electron) in the same way that SO (special orthogonal group) relates to O (orthogonal group) and SL (special linear group) relates to GL (general linear group). This is something some mathematicians find quite amusing.

Edit: also some say rng which is a ring without an identity (without an i). I think there are others similar to this.

elm stands for ELectronic Mail, if I'm not mistaken.

https://danhalbert.org/more.html

From the Latin word "catena", meaning "chain", which is also the source for the name of the catenary curve.

Less is more. That’s the joke.

I like how the name of "yes" promises that it will say "yes", but it actually says "y". But "yes no" makes it say "no"!

The emacs "JOKES" file contains an extended section of proposed backronyms, along with a bunch of other 20-30 year-old jokey bits from usenet:

https://github.com/emacs-mirror/emacs/blob/master/etc/JOKES

  EMACS may stand for "Editing MACroS," but some friends of mine suggested some more creative definitions.
  Here they are. Anyone have any additions?

  Eight Megabytes And Constantly Swapping
  Even a Master of Arts Comes Simpler
  ...

I've heard it as Emacs Makes All Computers Slow.

Probably was more applicable in the old days (as one call tell from the "megabytes" in the parent comment) than nowadays :)

Thats because it Eventually Mallocs All Computer Storage.

Escape-meta-alt-ctrl-shift!

I'm often surprised how Emacs can struggle sometimes on modern hardware, like for example when chain-executing complex keyboard macros - though mostly yeah, it doesn't apply all that much anymore.

Emacs is actually faster than most editors, but it lets you do anything so of course you can slow it down.

The issue is it remains non-concurrent and any code (macros, extensions, …) executes in place of the editor doing its thang, so any non-trivial operation (or trivial operation on an entire buffer) locks up the editor until it's done and does its thing.

And while it might technically be faster for the process, as is the case with e.g. STW GCs on large processes it 1. feels horrible and 2. as an editor is interactive it stops the user in their tracks and slows them down to hell

According to the OpenBSD manual, yp stands for "yellow pee"

https://man.openbsd.org/yp

As I recall, it used to be officially called Yellow Pages in SunOS, but there was a dispute with British Telecom which owned the trademark on Yellow Pages, so Sun changed its name.

Wikipedia has (https://en.wikipedia.org/wiki/Network_Information_Service) the same story I remember, though doesn't give a source for it:

> Because British Telecom PLC owned the name "Yellow Pages" as a registered trademark in the United Kingdom for its paper-based, commercial telephone directory, Sun changed the name of its system to NIS, though all the commands and functions still start with "yp".

I always thought Yellow Pages was a generic term, but that's only in the USA. In other countries it's a trademark and owned by specific countries. TIL.

I understood that it originally stood for "yellow pages" because it is a directory service, but that the phone company asserted their trademark on the term.

Sun also initially named their zones project “Kevlar” that they got a notice for...

https://wiki.smartos.org/display/DOC/Community+History

My favorite one of these stories is about the "butthead astronomer". :)

http://www.lettersofnote.com/2012/03/butt-head-astronomer.ht...

Off topic: Are the Yellow Pages still a thing?

In case you're asking about the older product, yes I still get a phone book on my porch every 6 months to a year with updated residential and business phone numbers, including ads for the businesses.

The pages aren't yellow, though.

UK: yes, we still get sent one (along with a residential directory). It's no longer phone directory sized though. Now midway between A4 and A5 sized and about a centimeter thick.

Also in the UK. The last Yellow Pages we received, about two months ago, had a large ‘Final Issue‘ highlight on the front. They’ve finally given up. I tried to dredge up some nostalgic feelings for it’s demise, but flicking through the contents I really couldn’t. About 40% of the ad space throughout the book was for one advertiser, Gas Safe Register, and I can only assume that got sold at a song to fill the space. I’d love to know the percentage of the population that are going to miss it. I can see why it’s no longer effective with search engines being what they are, but there must still be a decent number of (presumably older) people who don’t google when they need contact details.

The only nostalgia I have is for the adverts - the kids and the missletoe, fly fishing by JR Hartley, etc

Also UK: Yep - the 2018 edition will be the last printed one, apparently - then online only.

Sort of. UDDI had sought to replace yellow pages (and other colors) in the Java/SOA world of the mid 2000s. LDAP (successor to yp/nis) lost the page terminology on the way to standardization.

https://www.thestreet.com/story/14207102/1/the-yellow-pages-...

Also systemd: both a system daemon, and a reference to "Systeme D[ebrouille]", a French term for getting things done quick and dirty on the fly:

https://en.wikipedia.org/wiki/System_D

I am French, I know about "système D" but I never associated it with systemd.

"Système D" implies making use of what's available, it is hacking (the good kind). systemd is the opposite, it is nothing like a quick and dirty solution to a problem but a major architecture change that intends to replace these hacks with something cleaner.

If the french expression really was the origin of the "systemd" name, it has to be in a twisted kind of way, or some kind of private joke. It would be like calling an electric car "octane" or something like that.

Nor should you have. The systemd people themselves have been pointing out for years that it is "something completely different" and not the origin, let alone the correct spelling, of the name.

* https://freedesktop.org/wiki/Software/systemd/#spelling

> getting things done quick and dirty on the fly

sounds about right.

systemd is pretty much the exact opposite of that philosophy. Quick and dirty would be an init system that simply executed script files in a directory in asciibetical order and then bolts on a configuration language in the comments of those scritps when they become too hard to manage manually. And then extending that configuration language with X-* options when you need to add new keys but can't be sure a existing software doesn't already use those names differently.

The origin of `/etc` as the place for configuration files is also interesting.

It was originally meant for any files that didn't fit into any of the predefined categories like `bin`, `lib`, and `dev`, hence the name "etc".

https://unix.stackexchange.com/a/56172/295743

Equally the history of why we have /bin /sbin and /usr/bin. Lack of disk space. When the OS got too big for a single disk and expanded to a second the split came about. /home came about when they expanded to a third!

http://lists.busybox.net/pipermail/busybox/2010-December/074...

Also, remember that the /usr used to mean "user", as in, if you were "bob" then your home directory was /usr/bob. That dance was done twice!

Moving stuff to /usr/bin made sense after systems got too big for a single volume and you've got this directory on a nice, new spacious multi-megabyte disk (oooh!) In those ancient days of Unix the sysop acting as the "bin" user owned /bin and the files inside it and could overwrite them from tapes or compilation. (root would own the files in the sbin)

So /usr/bin technically started out as his or her home directory when logging in as that account... at least back then.

/usr/sbin only came about after /home became the colloquial location for home directories, such that you had parallel constructions for /bin and /sbin under /usr, and later, /usr/local just as you did at the root.

> So /usr/bin technically started out as his or her home directory […]

That sounds wrong. /usr/bin existed at least as early as V6, but the 'bin' user's home directory was /bin.

bc = Belinda's Calculator. Apparently named after Belinda Cherry. [1]; i don't know who that is, but i assume she needed to do arithmetic on a unix machine a long time ago.

There's an older unix calculator called dc, for desk calculator; dc uses reverse-Polish, so it's a pain to use if you didn't grow up using those weird old HP calculators (or writing Forth). My understanding is that bc began as a shell script which would translate infix expressions into RPN and pass them to dc.

These days, if i want to do sums, i fire up a Python interpreter, or just plug them into a Google search box or Firefox address bar. But back in the day, i would use bc.

[1] http://shannon.usu.edu.ru/Langs/LangList/Langs/B/Bc.htm

Yes, bc is useful. You can even pipe standard input into bc, and get the results of the calculations on standard output.

    bc -l

used to be the invocation I used a lot.

I do that Google thing myself nowadays too :) They can even give answers to factorial(n) and the like. Found that recently. Wouldn't be surprised if a lot more too.

I wonder why there few single character Unix commands? Was this intentional?

Purely speculation, but maybe because it makes a typo way more likely to invoke an actual command?

If say, "rm" was just "r" and "find" was just "f"... well those keys are right next to each other on a QWERTY keyboard after all. Oops.

I don't know if it's intentional, but it would tend to increase name collisions with shell variables.

Plus all the good one character commands were already taken by the standard text editor, ed(1). It would have caused confusion.

But commands and variables are in different namespaces.

Single letters were reserved for personal commands and aliases.

They were sent over a network. Every baud counts. And then the output had to have a fixed width (not necessarily a fixed length, since it may have been printed on paper) because of "display" size.

^ This, and also because the keyboards back then were very hard to type on.

There used to be a type where 80x24 character terminals were a luxury, and even a type where printing commands and ouput actually meant printing on paper. Unix was developped in these times.

One presentation on the topic claims that the keyboards of the day were very stiff, so they preferred typing as few characters as possible.

According to Hendrik Jan Thomassen [0] this is the reason.

[0] https://www.youtube.com/watch?v=h5-DRLfzqD0

Only one I know is w. Are to there others? Sometimes e is editor but I think that's alias

Arguably not original UNIX but: Practical Extraction and Reporting Language, aka Pathologically Eclectic Rubbish Lister aka `perl`

Which reminds me of my favorite one...

If Perl programs (executables, whatever you call them) are called "modules", why is the main place people download them from called CPAN?

It's completely illogical.

C = Comprehensive (It's not, it definitely does not contain all possible modules)

P = Perl (This is only one that makes sense)

A = Archive (If the things people create are called modules - .pm files, really - what makes this an archive? A collection of things? That's a weak leg to stand on. Yes, distributions formalizes this, but modules seems to be the common nomenclature.

N = Network (How is this a network? I think Wall - or later, Hietaniemi - just wanted people to think it was big and important in the early days)

This is all absurd and slightly sarcastic, but I finally got to write it down somewhere :)

CPAN was named after (in imitation of) CTAN, the Comprehensive TeX Archive Network. CTAN was named by George Greenwade — the idea was to bring together (network) various TeX archives that various people had collected. See:

• https://www.cpan.org/authors/id/H/HF/HFB/grok-cpan-1.01.pdf (page 3)

• https://ctan.org/ctan/?lang=en or http://dante.ctan.org/what_is_ctan.html

Imitation, flattery etc, etc.

As I said before, take this with a dose of sarcasm :)

There are multiple CPAN sites, which rsync from each other in a hierarchical way, so "network" is quite appropriate. And they retain all previous versions, so they're an archive. Also, the intention was for it to contain all published modules, and it has indeed grown to be, I think, the largest repository of modules for any language. Comprehensive does not mean complete.

Comprehensive does not mean "all possible items".

The archive is the collection of archive files which contains a combination of software libraries, documentation, programs, tests, and metadata. It also includes manifests, checksums and other data useful for the CPAN program.

The network is a collection of 250+ mirrors of the archives.

I hate to do this, but...

Well, actually...

https://www.google.com/search?q=comprehensive&ie=UTF-8&oe=UT...

On a more serious note, while I was not aware of how extensively mirrored CPAN is, there is something to be said for it being the canonical source.

Ok, I'll grant you "all" is in the defintion, but so is "nearly all". Comprehensive is often used with a modifier to denote that it doesn't cover all possibilities. It also is applied to subjects that can't include all possibilities, or where they can't reasonably be known. Its root word compréhensif also hints at the subject covering many areas, but not all of them; a thorough understanding.

CPAN covers nearly all Perl libraries, and also covers nearly all categories of modules, as they are organized into a hierarchy based on topic, and the modules' naming naturally falls into a hierarchy as well. It's easy to find a module even without a search engine, and thus easy to find out whether you need to make one or whether one already exists. The result is a comprehensive archive of libraries.

Perl programs are not necessarily modules.

Perl modules can be written to function as programs, a technique known as modulinos[0], but it is not a common approach.

[0]: https://www.masteringperl.org/category/chapters/modulinos/

They are mentioned in the article. Both of them are backronyms, though:

https://en.wikipedia.org/wiki/Perl#Name

There are a few accounts of how Perl got its name. Larry himself said this in a State of the Onion talk.

https://www.perl.com/pub/2005/09/22/onion.html/

> You might say that Perl grew out of the Cold War. I’ve often told the story about how Perl was invented at a secret lab that was working on a secret NSA project, so I won’t repeat that here, since it’s no secret. Some of you have heard the part about my looking for a good name for Perl, and scanning through /usr/dict/words for every three- and four-letter word with positive connotations. Though offhand, I can’t explain how I missed seeing Ruby. So anyway, I ended up with “Pearl” instead.

A Wired piece gives a deeper look.

https://www.wired.com/2000/10/cruise/?pg=3

> “Perl” is usually glossed as “Practical Extraction and Report Language,” and occasionally as “Pathetically Eclectic Rubbish Lister.” Both are retronyms. Originally, Larry wanted to name his new language Pearl, a word with positive connotations. Larry considers himself as much a linguist as a hacker. He’s also a fan of Tolkien’s Lord of the Rings. There are doorways into Tolkien’s imagination built right into the core of Perl. Each section of the source code begins with a quote from the Rings trilogy – say, “A fair jaw-cracker dwarf language must be.” If you understand the epigram, you comprehend what that section is designed to do. Larry wanted to give Perl a name that suggested that it was worth treasuring.

> Furthermore, Larry is a devout Christian – he’s the son of a fundamentalist Mennonite preacher from a long line of preachers. In the 13th book of Matthew, Jesus tells the parable of a merchant “seeking goodly pearls, who, when he had found one pearl of great price, went and sold all that he had, and bought it” – “it” being the Kingdom of Heaven. But there was already another programming language called Pearl. So Larry – whose personal motto, which has become the mantra of the Perl community, is “There’s more than one way to do it” – christened his new creation Perl.

I read somewhere that "Perl" isn't actually any kind of acronym but really stands for a pearl (the glossy ball thingy produced by certain species of sea life) - the reason being some kind of biblical reference to it.

pwd - took me forever to figure out this had nothing to do with a password. According to this article, it means "Print Working Directory":

https://unix.stackexchange.com/questions/399026/etymology-of...

"Historically, program output was printed on paper rather than on screens. So the print part is due to the output technology of the time that the command was developed."

I remap the 'p' as "present working directory"

>> The Perl language is Larry Wall's highly popular freely-available completely portable text, process, and file manipulation tool that bridges the gap between shell and C programming (or between doing it on the command line and pulling your hair out).

That's ...an interesting definition of Perl. Last I heard it was the "gaffer tape of the internet" or some such. I put off learning Perl for so long that I don't need to anymore. I wonder how often it's used nowadays.

I use it all the time.

I remember reading somewhere that supposedly when fsck was first introduced there was different letter in place of s.

Two more: Serious - ditroff - device independent troff Snarky - vi - vile (yah, I do emacs)

daemon - disk and execution monitor

Folk eymology. The origin is a reference to Maxwell's demon.

tac = cat, but in reverse

I've heard grep is for Globally find Regular Expression and Print (which comes from the :g/re/p command of ed).

Yep. It's second in the article :D

grep: global regex parser

No, that's not the origin of the name. Someone thought that up later. Also, the regex is globally matched, after having been parsed just once, so the name would not even make sense.

As explained in the article, it's actually Global Regular Expression Print.

Sudo !! - sudo's the last command

The double exclamation is a shell feature, though.

That's not what this page is about; unless you can tell us an interesting reason why the ! character was chosen.

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