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Some Unix Tricks

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34 pointskirubakaran9 comments

If you ever do end up with me interviewing you, I'll likely work one or two of these into the discussion to explore your level of knowledge about Unix.

Translation:

If you ever do end up with me interviewing you, I'll likely work one or two obscure questions into the discussion to make you feel stupid so that I can gloat. That's how charming I am.

When you face that situation, never answer it properly because it will probably piss him off! Answer something close to OK. Praise his skills when he enlightens you with his "right" answer. That will get you the job, if you still want to suffer working for him.

After the second tip I was expecting

echo $PASSWORD | compress -f > /etc/password

A good way to learn this sort of stuff is:

  for util in `ls $DIRNAME`; do whatis $util; done

where DIRNAME is /bin /sbin /usr/bin /usr/local/bin etc. depending on what Unix you're running.

Pick a couple that interest you and check out their man pages. Or, follow the SEE ALSO section in man pages.

For "Remove DOS ^M from ends of lines" most Linux distros (at least) have unix2dos and dos2unix.

    $ printf "test\r\n" > test.txt
    $ cat -A test.txt 
      test^M$
    $ dos2unix test.txt 
      dos2unix: converting file test.txt to UNIX format ...
    $ cat -A test.txt 
      test$

if not in your Debian path:

    apt-get install tofrodos

Well, I knew #4, and I could have figured out the rest if I needed to, but still, good to know.

I'm always surprised at how much of Unix's default command set is oriented towards text manipulation. People always argue between Vim and Emacs. I wonder if anyone's ever compared Emacs and Bash.

It's not a meaningful comparison because it's not an either/or. You can use said shell commands inside Emacs pretty easily: M-| is shell-command-on-region, with output to another buffer, and univ. argument M-| replaces the region with the command's output. Same with vi, for that matter: :1,10!sort pipes the first ten lines of file through sort, for example. vi has ex mode, all the commands starting with ":". Ex is basically an embedded sed.)

2. None of the shell command stuff is tied to bash -- you can use any of them with sh, ksh, zsh, etc.

It doesn't have to be an either/or for the comparison to be meaningful. As to the specicifity to Bash, I could have substituted 'shell' or Unix environment just the same and meant the same question, that is, the advantages of working within Emacs or Vim, versus do the same operations directly from the command prompt.

I usually run the command prompt inside Emacs, anyway -- it's another big text buffer to edit / copy from.

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