Commands using grep (1,935)

  • Quick key/value display within /proc or /sys

    Within /proc and /sys there are a lot of subdirectories, which carry pseudofiles with only one value as content. Instead of cat-ing all single files (which takes quite a time) or do a "cat *" (which makes it hard to find the filename/content relation), just grep recursively for . or use "grep . /blabla/*" (star instead of -r flag). For better readability you might also want to pipe the output to "column -t -s : ". Show Sample Output


    4
    grep -r . /sys/class/net/eth0/statistics
    olorin · 2009-08-05 08:20:39 3
  • grep (or anything else) many files with multiprocessor power

    xargs -P N spawns up to N worker processes. -n 40 means each grep command gets up to 40 file names each on the command line.


    4
    find . -type f -print0 | xargs -0 -P 4 -n 40 grep -i foobar
    ketil · 2009-08-05 23:18:44 8
  • Get your internal IP address and nothing but your internal IP address

    Will return your internal IP address. Show Sample Output


    4
    ifconfig $devices | grep "inet addr" | sed 's/.*inet addr:\([0-9\.]*\).*/\1/g'
    matthewbauer · 2009-08-06 21:43:22 3
  • grep certain file types recursively


    4
    find . -name "*.[ch]" | xargs grep "TODO"
    freestyler · 2009-08-12 16:53:01 5
  • total text files in current dir


    4
    file -i * | grep -c 'text/plain'
    markszabo · 2009-08-16 22:29:35 3
  • Find UTF-8 text files misinterpreted as ISO 8859-1 due to Byte Order Mark (BOM) of the Unicode Standard.

    Character: "?" is the Byte Order Mark (BOM) of the Unicode Standard. Specifically it is the hex bytes EF BB BF, which form the UTF-8 representation of the BOM, misinterpreted as ISO 8859/1 text instead of UTF-8. Show Sample Output


    4
    find . -type f | grep -rl $'\xEF\xBB\xBF'
    pfredrik · 2009-08-19 13:27:09 3
  • get the latest version

    to download latest version of "util", maybe insert a sort if they wont be shown in right order. curl lists all files on mirror, grep your util, tail -1 will gets the one lists on the bottom and get it with wget Show Sample Output


    4
    mirror=ftp://somemirror.com/with/alot/versions/but/no/latest/link; latest=$(curl -l $mirror/ 2>/dev/null | grep util | tail -1); wget $mirror/$latest
    peshay · 2009-08-24 15:58:31 282
  • List of reverse DNS records for a subnet

    This command uses nmap to perform reverse DNS lookups on a subnet. It produces a list of IP addresses with the corresponding PTR record for a given subnet. You can enter the subnet in CDIR notation (i.e. /24 for a Class C)). You could add "--dns-servers x.x.x.x" after the "-sL" if you need the lookups to be performed on a specific DNS server. On some installations nmap needs sudo I believe. Also I hope awk is standard on most distros. Show Sample Output


    4
    nmap -R -sL 209.85.229.99/27 | awk '{if($3=="not")print"("$2") no PTR";else print$3" is "$2}' | grep '('
    netsaint · 2009-09-02 16:33:15 5
  • Show apps that use internet connection at the moment.

    This corrects duplicate output from the previous command. Show Sample Output


    4
    netstat -lantp | grep -i establ | awk -F/ '{print $2}' | sort | uniq
    HarimaKenji · 2009-09-19 14:42:31 7
  • Play random music from blip.fm


    4
    mpg123 `curl -s http://blip.fm/all | sed -e 's#"#\n#g' | grep mp3$ | xargs`
    torrid · 2009-11-07 14:48:01 7
  • Shows you how many hours of avi video you have.

    midentify.sh is part of mplayer, but you might have to locate it on your box. Show Sample Output


    4
    /usr/share/mplayer/midentify.sh `find . -name "*.avi" -print` | grep ID_LENGTH | awk -F "=" '{sum += $2} END {print sum/60/60; print "hours"}'
    equant · 2009-11-17 03:33:20 11
  • count and number lines of output, useful for counting number of matches

    Write each FILE to standard output, with line numbers added. With no FILE, or when FILE is -, read standard input. Show Sample Output


    4
    ps aux | grep [a]pache2 | nl
    donnoman · 2009-12-17 18:48:09 4
  • Find unused IPs on a given subnet

    Somewhat shorter version. Show Sample Output


    4
    fping -r1 -g <subnet> 2> /dev/null | grep unreachable | cut -f1 -d' '
    unixmonkey7953 · 2010-01-22 09:07:04 3
  • recursive search and replace old with new string, inside files

    xargs deals badly with special characters (such as space, ' and "). To see the problem try this: touch important_file touch 'not important_file' ls not* | xargs rm Parallel https://savannah.nongnu.org/projects/parallel/ does not have this problem.


    4
    grep -rl oldstring . | parallel sed -i -e 's/oldstring/newstring/'
    unixmonkey8046 · 2010-01-28 08:44:16 6
  • See your current RAM frequency

    Show Sample Output


    4
    /usr/sbin/dmidecode | grep -i "current speed"
    eastwind · 2010-02-19 07:28:07 5
  • set desktop background to highest-rated image from Reddit /r/wallpapers

    You'll need "feh" to set the background from the commandline. Install with "apt-get install feh" Thanks to the Redditors on this thread: http://www.reddit.com/r/linux/comments/bira4/is_there_a_linux_version_of_this_preferably_a/


    4
    curl http://www.reddit.com/r/wallpapers.rss | grep -Eo 'http:[^&]+jpg' | head -1 | xargs feh --bg-seamless
    shavenwarthog · 2010-03-27 00:08:40 5
  • Determine whether a CPU has 64 bit capability or not

    Check if you have 64bit by looking for "lm" in cpuinfo. lm stands for "long mem". This can also be used without being root.


    4
    if cat /proc/cpuinfo | grep " lm " &> /dev/null; then echo "Got 64bit" ; fi
    xeor · 2010-04-10 15:31:58 6
  • Grab a list of MP3s out of Firefox's cache

    Ever gone to a site that has an MP3 embedded into a pesky flash player, but no download link? Well, this one-liner will yank the names of those tunes straight out of FF's cache in a nice, easy to read list. What you do with them after that is *ahem* no concern of mine. ;) Show Sample Output


    4
    for i in `ls ~/.mozilla/firefox/*/Cache`; do file $i | grep -i mpeg | awk '{print $1}' | sed s/.$//; done
    BoxingOctopus · 2010-04-11 23:14:18 7
  • embed referred images in HTML files

    in "a.html", find all images referred as relative URI in an HTML file by "src" attribute of "img" element, replace them with "data:" URI. This useful to create single HTML file holding all images in it, as a replacement of the IE-created .mht file format. The generated HTML works fine on every other browser except IE, as well as many HTML editors like kompozer, while the .mht format only works for IE, but not for every other browser. Compare to the KDE's own single-file-web-page format "war" format, which only opens correctly on KDE, the HTML file with "data:" URI is more universally supported. The above command have many bugs. My commandline-fu is too limited to fix them: 1. it assume all URLs are relative URIs, thus works in this case: <img src="images/logo.png"/> but does not work in this case: <img src="http://www.my_web_site.com/images/logo.png" /> This may not be a bug, as full URIs perhaps should be ignored in many use cases. 2. it only work for images whoes file name suffix is one of .jpg, .gif, .png, albeit images with .jpeg suffix and those without extension names at all are legal to HTML. 3. image file name is not allowed to contain "(" even though frequently used, as in "(copy of) my car.jpg". Besides, neither single nor double quotes are allowed. 4. There is infact a big flaw in this, file names are actually used as regular expression to be replaced with base64 encoded content. This cause the script to fail in many other cases. Example: 'D:\images\logo.png', where backward slash have different meaning in regular expression. I don't know how to fix this. I don't know any command that can do full text (no regular expression) replacement the way basic editors like gedit does. 5. The original a.html are not preserved, so a user should make a copy first in case things go wrong.


    4
    grep -ioE "(url\(|src=)['\"]?[^)'\"]*" a.html | grep -ioE "[^\"'(]*.(jpg|png|gif)" | while read l ; do sed -i "s>$l>data:image/${l/[^.]*./};base64,`openssl enc -base64 -in $l| tr -d '\n'`>" a.html ; done;
    zhangweiwu · 2010-05-05 14:07:51 13
  • List processes playing sound

    When trying to play a sound you may sometimes get an error saying that your sound card is already used, but not by what process. This will list all processes playing sound, useful to kill processes that you no longer need but that keep using your sound card. Show Sample Output


    4
    lsof | grep pcm
    Miles · 2010-05-16 12:12:01 3
  • Print number of mb of free ram

    This will show the amount of physical RAM that is left unused by the system. Show Sample Output


    4
    grep '^MemFree:' /proc/meminfo | awk '{ mem=($2)/(1024) ; printf "%0.0f MB\n", mem }'
    dbbolton · 2010-06-30 18:33:29 3
  • Upload folder to imageshack.us (forum)

    Each file in the current folder is uploaded to imageshack.us If the folder contains other filetypes change: for files in * to: for files in *.jpg (to upload ONLY .jpg files) Additionally you can try (results may vary): for files in *.jpg *.png The output URL is encased with BB image tags for use in a forum. Show Sample Output


    4
    imageshack() { for files in *; do curl -H Expect: -F fileupload="@$files" -F xml=yes -# "http://www.imageshack.us/index.php" | grep image_link | sed -e 's/<image_link>/[IMG]/g' -e 's/<\/image_link>/[\/IMG]/g'; done; }
    operatinghazard · 2010-10-01 06:50:04 6
  • Remove comments and empty lines from a conf file

    Some conf file are very long (squid.conf) This command help to read it.


    4
    grep ^[^#] /etc/file.conf
    longdrink · 2010-10-20 12:26:34 9
  • Retrieve a random command from the commandlinefu.com API

    Can be integrated into your .bashrc if you like. You'll probably want to grep out my name. Show Sample Output


    4
    lynx --dump http://www.commandlinefu.com/commands/random/plaintext | grep .
    root · 2010-12-04 20:53:10 5
  • Arch Linux sort installed packages by size

    This one-liner will output installed packages sorted by size in Kilobytes. Show Sample Output


    4
    paste <(pacman -Q | awk '{ print $1; }' | xargs pacman -Qi | grep 'Size' | awk '{ print $4$5; }') <(pacman -Q | awk '{print $1; }') | sort -n | column -t
    BruceLEET · 2011-01-07 18:43:18 7
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find previously entered commands (requires configuring .inputrc)
[Click the "show sample output" link to see how to use this keystroke.]   Meta-p is one of my all time most used and most loved features of working at the command line. It's also one that surprisingly few people know about. To use it with bash (actually in any readline application), you'll need to add a couple lines to your .inputrc then have bash reread the .inputrc using the bind command:   $ echo '"\en": history-search-forward' >> ~/.inputrc   $ echo '"\ep": history-search-backward' >> ~/.inputrc   $ bind -f ~/.inputrc     I first learned about this feature in tcsh. When I switched over to bash about fifteen years ago, I had assumed I'd prefer ^R to search in reverse. Intuitively ^R seemed better since you could search for an argument instead of a command. I think that, like using a microkernel for the Hurd, it sounded so obviously right fifteen years ago, but that was only because the older way had benefits we hadn't known about.     I think many of you who use the command line as much as I do know that we can just be thinking about what results we want and our fingers will start typing the commands needed. I assume it's some sort of parallel processing going on with the linguistic part of the brain. Unfortunately, that parallelism doesn't seem to work (at least for me) with searching the history. I realize I can save myself typing using the history shortly after my fingers have already started "speaking". But, when I hit ^R in Bash, everything I've already typed gets ignored and I have to stop and think again about what I was doing. It's a small bump in the road but it can be annoying, especially for long-time command line users. Usually M-p is exactly what I need to save myself time and trouble.     If you use the command line a lot, please give Meta-p a try. You may be surprised how it frees your brain to process more smoothly in parallel. (Or maybe it won't. Post here and let me know either way. ☺)

output length of longest line
If your wc does not have the -L option, you can use awk.

cut audio file

Setting global redirection of STDERR to STDOUT in a script
You have a script where =ALL= STDERR should be redirected to STDIN and you don't want to add "2>&1" at the end of each command... E.G.: $ ls -al /foo/bar 2>&1 Than just add this piece of code at the beginning of your script! I hope this can help someone. :)

Find usb device in realtime
Using this command you can track a moment when usb device was attached.

Stop Flash from tracking everything you do.
Brute force way to block all LSO cookies on a Linux system with the non-free Flash browser plugin. Works just fine for my needs. Enjoy.

Print the contents of $VARIABLE, six words at a time
Print out the contents of $VARIABLE, six words per line, ignoring any single or double quotes in the text. Useful when $VARIABLE contains a sentence that changes periodically, and may or may not contain quoted text.

unbuffered tcpdump
Sometimes the question comes up: How to get unbuffered tcpdump output into the next program in the pipe? i.e. if your OS forces you to wait for the buffer to fill before the next program sees any of the output If you use -Uw- then you can't use -A (or -X or -XX) at the same time. When the question comes up, I've never seen anyone suggest this simple solution: chaining 2 tcpdump instances.

Given $PID, print all child processes on stdout
Simpler.

Git Global search and replace
Find all the occurrences in the git repo of 'foo' and replace with 'bar'

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