What does the 'rc' in `.bashrc`, etc. mean?
superuser.com
superuser.com
> [Unix: from `runcom files' on the CTSS system 1962-63, via the startup script /etc/rc] Script file containing startup instructions for an application program (or an entire operating system), usually a text file containing commands of the sort that might have been invoked manually once the system was running but are to be executed automatically each time the system starts up. See also dot file, profile (sense 1).
"rc-file" does not seem to be present pre-ESR, however: https://jargon-file.org/archive/jargon-1.0.3.dos.txt
The gnu project was developed on a vax running Unix that somehow had been installed at the AI lab. Nobody used it so RMS decided to use it as a development machine. We had our own OSes, languages, and hardware and at that point in time Unix offered significantly less power for a large investment of effort.
I've always found obscure historical operating systems fascinating.
https://github.com/freebsd/freebsd/blob/master/sbin/init/ini...
Not to be confused with zombocom.
.profile is only for login sessions, .shrc is sourced on every shell fork, about 1000x more than .profile.
For example, do you want to make an autoloaded function named "foo" that comes into existence the first time you call it? Write a file named ~/.config/fish/functions/foo.fish, and inside it define a function named "foo". There - done.
Follow this pattern to make a function named "fish_greeting", and it will run every time you launch a new fish shell. Want to make a custom prompt? Write a function named "fish_prompt". Decide you want one of those fancy prompts where the timestamp is displayed on the right side of your terminal window? Make a "fish_right_prompt.fish" file and put in it:
function fish_right_prompt --description 'Write out the right prompt'
set_color 666666
date +'%Y-%m-%d %H:%M:%S'
set_color normal
end
* There are two scripts run by a login shell, $HOME/.profile and /etc/profile .
* These scripts set up environment variables and other things (e.g. umask) to be inherited by the whole login session.
* They, specifically, optionally set an ENV variable whose value names a third script that is run by every interactive shell, including the interactive login shell.
That's exactly three scripts: one for the system administrator and another one for the user to set up login-session-wide stuff, and one for the user to set up this-interactive-shell stuff (such as the shell variables for fancy prompts, completion settings, command-line editing stuff, useful interactive shell aliases, and whatnot). They are always in the same order. And they are simply based upon two things: whether the shell is a login shell, and whether the shell is an interactive shell.
The C shell mechanism is similarly simple, on its own.
The complexity mainly comes from the fact that the Bourne Again shell and the Z shell, amongst others, have multiple mechanisms mixed together and extensions. They look for scripts that are specifically in their own shell languages rather than potentially shared with other shells; .zprofile and .bash_profile instead/ahead of .profile , for example. They have extra scripts that mirror the C shell way of doing things; .zlogin, .zlogout, .bash_login, .bash_logout, .bashrc, and .zshrc, for example. They have idiosyncratic and non-strictly-standard ways of deciding what constitutes an interactive shell. They have mechanisms for disabling the extensions, and ways to come up in alternative not-strictly-conformant sh-compatible modes.
info bash -n "Bash Startup Files"
Maybe unlikely but maybe still, this is one of those things how language evolves where a word/suffix has an original meaning that is lost in the practical use day today.
Well, at least! I had no idea the meaning behind it, and it amazes me how I never think it about it.
"The .rc Suffix (Origin Story)
Most UNIX commands use the suffix rc for the name of configuration files. According to Wikipedia, this extension isn’t an acronym for “resource configuration” or “runtime configuration” but comes from a command called RUNCOM.
RUNCOM was created by Louis Pouzin for the Compatible Time-Sharing System (CTSS), which was one of the first time-sharing operating systems. RUNCOM was used to execute a series of commands in succession—a precursor to what we now call a shell script.
He is even credited with coining the term shell, as he describes in a post on the Internet from 2000 on the origins of the shell:
'After having written dozens of commands for CTSS, I reached the stage where I felt that commands should be usable as building blocks for writing more commands, just like subroutine libraries. Hence, I wrote “RUNCOM”, a sort of shell driving the execution of command scripts, with argument substitution. The tool became instantly most popular [sic], as it became possible to go home in the evening while leaving behind long runcoms executing overnight.
Without being invited on the subject, I wrote a paper explaining how the Multics command language could be designed with [the] objective [of using commands somehow like a programming language]. And I coined the word “shell” to name it.'
Although RUNCOM (and CTSS) has long-been retired from regular use, its legacy lives on both as the name for user-specific configuration files and as the basis for the UNIX start-up scripts, typically located in /etc/rc.d."
[0] https://pragprog.com/book/dccar2/build-awesome-command-line-...
r 13:41 0.055 7
ls >sc1>system_start_up.ec
Segments = 1, Lengths = 2.
r w 2 system_start_up.ec
The comments are more interesting than the Wikipedia article...
In source code sometimes a longer name really helps, but then some people take it to the extreme and make everything look pretty ugly and tedious to work with.
In this case, I guess it would not had been that bad to name the files `.bash.runcommands`. `.bourne-again-shell.run-commands`: maybe too much :-)
Just google for "rc unix meaning", as I did. Have to acknowledge I didn't know it either. But now we all know. Good question.
Edit: more info here, https://en.wikipedia.org/wiki/Run_commands .
FYI, the link mentions not only 'run commands' but also 'resource control', 'run control', and 'runtime configuration'.
Instead of bashing a stranger to google, reading the link might be more productive.
Yet, if they felt like it was a waste of time they wouldn't bother answering those people at all. It's not like anyone is forced to respond to someone asking a question with an easily searched for answer. But people choose to, so they obviously must feel like it's a good use of their time.
Reminds me a lot of Googling some programming question, it pointing me at a highly upvoted Stack Overflow question, only to see comments on the question like "voting to close. do some research first" or (also often) some moderator has closed it as "not useful" or something like that.
To be fair, I actually made a search like that recently and was directed to quora which actually had a question and answer related to the dogs I was searching for.
And the people answering aren’t always the same people; it’s a useful thing to practise explaining something, so it’s useful to have a rolling set of basic questioners to write answers for. It’s not wasted time, it’s beneficial time.
Also, let's not compare <pero vs perro> to <learning spanish in a classroom>. If you have a teacher/mentor in front of you, sure, cache-hit them with your easily googleable questions. But when you spend 30 seconds making a Reddit submission to save you 3 seconds of googling, what exactly are you accomplishing?
It also does a disservice to the person always asking these questions who never learns to be resourceful. In my ideal world, LMGTFY is just some tough love. Like, now everyone has google in their pocket and I only see an uptick in trivial questions. And I think it's because we baby everyone with the mentality seen in your comment instead of training people to be self-reliant.
It's like when people ask what `const [a, b] = [1, 2]` in #javascript instead of just... trying it. Just do it. See what happens. That's how we need to be training people to learn, not baby them.
You might have seen someone say "welcome to learning Spanish, if you have any questions just ask!" and simply believed them instead of thinking it was a sperglord den where people were waiting to jump on you for not asking superior enough questions, for one thing. The sidebar of /r/learnspanish even says "If you have a question about anything Spanish-language related, ask and we'll help the best we can!".
For another, when learning something new you're pushing the edge of what you're capable of - what you want is a direct answer to just this sticking point, not a video of "5000 words every beginner MUST know!" or a page of "Twenty False cognates" which might have the answer, or a page of "Introductory Spanish" which is an advert for a training course in another country which isn't even running and hoping you can divert your already-strained attention to digging an answer out of a lot of unrelated stuff; asking a narrow, focused question on just the thing you need might be as much as you can manage. And as you say, you would ask a teacher, you would ask a friend, you would ask an IRC/Discord/etc chat, why would you assume you can't just ask Reddit?
I get it, /r/powershell is full of "how do I get rid of {Name=bob} in my output" because they don't understand the object pipeline, and I answer the ones I want to answer and ignore the ones I don't want to; it simply isn't a sub dedicated to catering "interesting questions for me", and the people who are learning powershell are mostly people with no programming background whatsoever, they're already lost in a pile of syntax, terminology, new tools, grandfathered-in-weird-behaviour, ancient Windows behaviour, filesystem name limitations, web character encoding weirdness, and just can't deal with stopping their five line script to take a course in object orientation before getting any further feedback.
> Like, now everyone has google in their pocket and I only see an uptick in trivial questions. And I think it's because we baby everyone with the mentality seen in your comment instead of training people to be self-reliant.
Agile programmer "Uncle" Bob Martin gave a talk in 2016[1] where he covers the history of programming, from 1 programmer in 1945, through millions in 2016, and estimates a growth rate of number of worldwide programmers doubling every 5 years - that is, every 5 years for the past 70 years, most of the programmers in the world have <6 years experience, continuous state.
You should expect that "everyone has Google in their pocket" leads to an uptick in simple questions simply through growth of people with smartphones, because most people who have a smartphone didn't grow up with the internet, didn't grow up with Google, likely isn't their main hobby or interest, haven't had one (with lots/unlimited mobile data) all that long.
I checked in my copy of the jargon file (which I downloaded in August 2001) and got:
rc file /R-C fi:l/ n.
[Unix: from `runcom files' on the CTSS system 1962-63, via the startup script /etc/rc] Script file containing startup instructions for an application program (or an entire operating system), usually a text file containing commands of the sort that might have been invoked manually once the system was running but are to be executed automatically each time the system starts up. See also dot file, profile (sense 1)