Commands by inof (7)

  • Some commands (such as sed and perl) have options to support in-place editing of files, but many commands do not. This shell function enables any command to change files in place. See the sample output for many examples. The function uses plain sh syntax and works with any POSIX shell or derivative, including zsh and bash. Show Sample Output


    1
    inplace() { eval F=\"\$$#\"; "$@" > "$F".new && mv -f "$F".new "$F"; }
    inof · 2010-04-09 11:36:31 8
  • Several people have submitted commands to do this, but I think this is the simplest solution. It also happens to be the most portable one: It should work with any sh or csh derived shell under any UNIX-like OS. Oh by the way, with my German locale ($LC_TIME set appropriately) it prints "g" most of the time, and sometimes (on Wednesdays) it prints "h". It never prints "y". Show Sample Output


    3
    date +%A | tail -2c
    inof · 2010-04-08 15:14:06 0
  • That one works on Linux. On BSD and Solaris, the ifconfig output is much easier to parse: /sbin/ifconfig -a | awk '/inet/{print $2}'


    0
    /sbin/ifconfig | awk -F'[ :]+' '/inet addr/{print $4}'
    inof · 2009-07-21 14:18:17 2
  • This is *NOT* about the -i option in grep. I guess everybody already knows that option. This is about the basic rule of life that the simplest things are sometimes the best. ;-) One day when I used "grep -i" for the umpteenth time, I decided to make this alias, and I've used it ever since, probably more often than plain grep. (In fact I also have aliases egrip and fgrip defined accordingly. I also have wrip="grep -wi" but I don't use this one that often.) If you vote this down because it's too trivial and simplistic, that's no problem. I understand that. But still this is really one of my most favourite aliases.


    -2
    alias grip="grep -i"
    inof · 2009-07-21 11:12:15 2
  • This alias finds identical lines in a file (or pipe) and prints a sorted count of them (the name "sucs" descends from the first letters of the commands). The first example shows the number of logins of users; the one who logged in most often comes last. The second example extracts web client IP addresses from a log file, then pipes the result through the "sucs" alias to find out which clients are performing the most accesses. Or pipe the first column of ps(1) output through "sucs" to see how many processes your users are running. Show Sample Output


    0
    alias sucs="sort | uniq -c | sort -n"
    inof · 2009-07-21 10:55:06 0
  • This shell snippet reads a single keypress from stdin and stores it in the $KEY variable. You do NOT have to press the enter key! The key is NOT echoed to stdout! This is useful for implementing simple text menus in scripts and similar things.


    5
    stty cbreak -echo; KEY=$(dd bs=1 count=1 2>/dev/null); stty -cbreak echo
    inof · 2009-06-09 13:15:49 4

  • 5
    awk '/match/{print NR}' file
    inof · 2009-06-03 17:34:13 3

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Swap a file or dir with quick resotre
This lets you replace a file or directory and quickly revert if something goes wrong. For example, the current version of a website's files are in public_html. Put a new version of the site in public_html~ and execute the command. The names are swapped. If anything goes wrong, execute it again (up arrow or !!).

Random IPv4 address

Show all detected mountable Drives/Partitions/BlockDevices
Yields entries in the form of "/dev/hda1" etc. Use this if you are on a new system and don't know how the storage hardware (ide, sata, scsi, usb - with ever changing descriptors) is connected and which partitions are available. Far better than using "fdisk -l" on guessed device descriptors.

Find all folder in /var that contains log in their path and have more than 10 files inside them, print the folder and the count
-L is for following symbolic links, it can be omitted and then you can find in your whole / dir

bash-quine
this command prints itself out. it doesn't need to be stored in a file and it isn't as easy as $ echo $BASH_COMMAND for information on quines see http://en.wikipedia.org/wiki/Quine_(computing)

Update all packages installed via homebrew
As of March 7, 2012: $ brew update - downloads upgraded formulas $ brew upgrade [FORMULA...] - upgrades the specified formulas $ brew outdated - lists outdated installations Note updating all packages may take an excruciatingly long time. You might consider a discriminating approach: run `brew outdated` and select specific packages needing an upgrade. For more information see homebrew's git repository: https://github.com/mxcl/homebrew

Fetch the current human population of Earth
Fetches the world population JSON data from the US census and parses it uses jshon

Check hashes of files installed by Debian packages, reporting only errors.

Get the full path to a file
Part of coreutils - so needs no extra package...

Get all files of particular type (say, PDF) listed on some wegpage (say, example.com)
This example command fetches 'example.com' webpage and then fetches+saves all PDF files listed (linked to) on that webpage. [*Note: of course there are no PDFs on example.com. This is just an example]


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