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"


    49
    date -d@1234567890
    kFiddle · 2009-04-11 22:26:41 20
  • 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 83
  • 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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dump database from postgresql to a file

Keep a copy of the raw Youtube FLV,MP4,etc stored in /tmp/
Certain Flash video players (e.g. Youtube) write their video streams to disk in /tmp/ , but the files are unlinked. i.e. the player creates the file and then immediately deletes the filename (unlinking files in this way makes it hard to find them, and/or ensures their cleanup if the browser or plugin should crash etc.) But as long as the flash plugin's process runs, a file descriptor remains in its /proc/ hierarchy, from which we (and the player) still have access to the file. The method above worked nicely for me when I had 50 tabs open with Youtube videos and didn't want to have to re-download them all with some tool.

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Change the homepage of Firefox
Pros: Works in all Windows computers, most updated and compatible command. Cons: 3 liner Replace fcisolutions.com with your site name.

Found how how much memory in kB $PID is occupying in Linux
The "proportional set size" is probably the closest representation of how much active memory a process is using in the Linux virtual memory stack. This number should also closely represent the %mem found in ps(1), htop(1), and other utilities.

Copy without overwriting

put current directory in LAN quickly

bash screensaver off

Performance tip: compress /usr/
Periodically run the one-liner above if/when there are significant changes to the files in /usr/ = Before rebooting, add following to /etc/fstab : = $ /squashed/usr/usr.sfs /squashed/usr/ro squashfs loop,ro 0 0 $ usr /usr aufs udba=reval,br:/squashed/usr/rw:/squashed/usr/ro 0 0 No need to delete original /usr/ ! (unless you don't care about recovery). Also AuFS does not work with XFS

Remount root in read-write mode.
Saved my day, when my harddrive got stuck in read-only mode.


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