Commands by kFiddle (10)

  • The symlinks command can show status of all symbolic links, including which links are dangling, which symlinks point to files on other file systems, which symlinks use ../ more than necessary, which symlinks are messy (e.g. having too many slashes or dots), etc. Other useful things it can do include removing all dangling links (-d) and converting absolute links to relative links (-c). The path given must be an absolute path (which is why I used $(pwd) in the example command).


    6
    symlinks -r $(pwd)
    kFiddle · 2009-05-01 23:33:10 10
  • Most of you are probably familiar with the "apropos" command for searching man pages. However, did you know there's a similar command inside of gdb? If, for example, you wanted to know all gdb commands that related to threads, you could type "apropos thread". Type "help some_command" to receive more information about a command. Type "help" by itself to see a list of help topics.


    0
    gdb command: apropos <keyword>
    kFiddle · 2009-05-01 23:19:35 4
  • Sometimes "ls" is just too slow, especially if you're having problems with terminal scroll speed, or if you're a speed freak. In these situations, do an echo * in the current directory to immediately see the directory listing. Do an echo * | tr ' ' '\n' if you want a column. Do an alias ls='echo *' if you want to achieve higher echelons of speed and wonder. Note that echo * is also useful on systems that are so low in memory that "ls" itself is failing - perhaps due to a memory leak that you're trying to debug.


    -5
    echo *
    kFiddle · 2009-04-17 21:40:58 9
  • I've seen some versions of hostname that don't have the -i option, so this may not work everywhere. When available, it's a better alternative than using ifconfig and wasting eyeball muscle to search for the address, and it's definitely simpler than using awk/sed.


    -2
    hostname -i
    kFiddle · 2009-04-17 21:26:56 7
  • This is a simple command, but extremely useful. It's a quick way to search the file names in the current directory for a substring. Normally people use "ls *term*" but that requires the stars and is not case insensitive. Color (for both ls and grep) is an added bonus.


    6
    alias lg='ls --color=always | grep --color=always -i'
    kFiddle · 2009-04-11 23:15:12 8
  • Reduce the number of keystrokes it takes to open a file in vim. First of all, you just need to type "v", which is less than half the number of characters (!), and second-of-all, you only need to enter a substring of the file you want to open. For example, if you want to open the file, homework.txt, then type "v hom" to open it. Good tip is to use the lowest unique substring, otherwise you'll open multiple files in different buffers (which is sometimes desirable). Use Ctrl-^ to switch between buffers.


    0
    function v { if [ -z $1 ]; then vim; else vim *$1*; fi }
    kFiddle · 2009-04-11 23:06:43 8
  • This example, for example, produces the output, "Fri Feb 13 15:26:30 EST 2009"


    50
    date -d@1234567890
    kFiddle · 2009-04-11 22:26:41 29
  • Have a grudge against someone on your network? Do a "find -writable" in their directory and see what you can vandalize! But seriously, this is really useful to check the files in your own home directory to make sure they can't inadvertently be changed by someone else's wayward script.


    4
    find -writable
    kFiddle · 2009-04-11 22:16:35 6
  • Info has some of the worst keybindings I've ever seen. Being a vim user, I attribute that to emacs influence. Use the --vi-keys option to use some of the vi keybindings, although this won't change all the keybindings. Use the "infokey" program to have more control over info keybindings.


    8
    info --vi-keys
    kFiddle · 2009-04-11 22:10:08 85
  • Although less behaves more or less like vim in certain aspects, the vim regex for word boundaries (\< and \>) do not work in less. Instead, use \b to denote a word boundary. Therefore, if you want to search for, say, the word "exit", but do not want to search for exiting, exits, etc., then surround "exit" with \b. This is useful if you need to search for specific occurrences of a keyword or command. \b can also be used at just the beginning and end, if needed.


    5
    \bTERM\b
    kFiddle · 2009-04-11 22:05:12 6

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find broken symbolic links
== remove broken links == find -L . -type l -exec rm -rf {} \; == how this work == "symbolic link; this is never true if the -L option or the -follow option is in effect, unless the symbolic link is broken. If you want to search for symbolic links when -L is in effect, use -xtype." -- manpage of find.

Get MX records for a domain

Show apps that use internet connection at the moment. (Multi-Language)
for one line per process: $ ss -p | cat for established sockets only: $ ss -p | grep STA for just process names: $ ss -p | cut -f2 -sd\" or $ ss -p | grep STA | cut -f2 -d\"

Get me yesterday's date, even if today is 1-Mar-2008 and yesterday was 29-Feb-2008
Fool date by setting the timezone out by 24 hours and you get yesterday's date. Try TZ=XYZ-24 to get tomorrow's date. I live in TZ=GMT0BST so you might need to shift the number 24 by the hours in your timezone.

Finding the number of cpu's

Huh? Where did all my precious space go ?
Sort ls output of all files in current directory in ascending order Just the 20 biggest ones: $ ls -la | sort -k 5bn | tail -n 20 A variant for the current directory tree with subdirectories and pretty columns is: $ find . -type f -print0 | xargs -0 ls -la | sort -k 5bn | column -t And finding the subdirectories consuming the most space with displayed block size 1k: $ du -sk ./* | sort -k 1bn | column -t

Mapreduce style processing
parallel can be installed on your central node and can be used to run a command multiple times. In this example, multiple ssh connections are used to run commands. (-j is the number of jobs to run at the same time). The result can then be piped to commands to perform the "reduce" stage. (sort then uniq in this example). This example assumes "keyless ssh login" has been set up between the central node and all machines in the cluster. bashreduce may also do what you want.

Google Translate
$ translate [output-language] [source-language] 1) "some phrase" should be in quotes 2) [output-language] - optional (default: English) 3) [source-language] - optional (default: auto) $ translate "bonjour petit lapin" hello little rabbit $ translate "bonjour petit lapin" en hello little rabbit $ translate "bonjour petit lapin" en fr hello little rabbit

print text in colors green, cyan, blue or red (see sample output for usage)

bash screensaver (scrolling ascii art with customizable message)
Displays a scrolling banner which loops until you hit Ctrl-C to terminate it. Make sure you finish your banner message with a space so it will loop nicely.


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