Commands by warkruid (2)

  • Listen and sort your music, with prompt for deleting (minimal alternative version)

    The glob pattern * expands to all files, no need for the 'ls' command. The quotes around "$i" make sure filenames with spaces in them are handled correctly. mplayer determines if it is a media file and plays it, or gives errors and the loop asks if this file has to be removed. Show Sample Output


    -1
    for i in *; do mplayer "$i" && rm -i "$i"; done
    warkruid · 2013-12-26 17:13:23 0
  • Poor man's

    I sometimes have use an usb stick to distribute files to several standalone "internet" pc's. I don't trust these machines period. The sticks I have do not have a write protection. So as a added security measure I fill the unused space on the (small) usb stick with a file with randomly generated bits. Any malware that tries to write to this stick will find no space on it. Tested on slackware 14 Note: you may need root access to write to the device. This depends on your mount options. Show Sample Output


    0
    set +e +u; dd if=/dev/urandom of="/media/usb1/$$";sync;sync
    warkruid · 2013-12-22 14:35:53 0

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

Share Your Commands

Check These Out

mount a cdrom

Re-read partition table on specified device without rebooting system (here /dev/sda).

Clear your history saved into .bash_history file!
Note the space before the command; that prevents your history eliminating command from being recorded. ' history -c && rm -f ~/.bash_history' Both steps are needed. 'history -c' clears what you see in the history command. 'rm -f ~/.bash_history' deletes the history file in your home directory.

Outputs files with ascii art in the intended form.
Files containing ascii art (e.g. with .nfo extension) are typically not correctly reproduced at the command line when using cat. With iconv one can easily write a wrapper to solve this: $ #!/bin/bash $ if [ -z "$@" ]; then echo "Usage: $(basename $0) file [file] ..." $ else iconv -f437 -tutf8 "$@"; fi $ exit 0

Convert PNG to GIF
(relies on 'imagemagick') Convert all .png files to .gif. This can also go the other way if you reverse the file extensions in the command, e.g.: $ for file in *.gif; do convert "$file" "$(basename $file .gif).png"; done If the file is named 'example1.png' it will be named 'example1.gif' when it is complete.

Find files that have been modified on your system in the past 60 minutes
Useful mainly for debugging or troubleshooting an application or system, such as X11, Apache, Bind, DHCP and others. Another useful switch that can be combined with -mmin, -mtime and so forth is -daystart. For example, to find files that were modified in the /etc directory only yesterday: $ sudo find /etc -daystart -mtime 1 -type f

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Find out which debian package a command (executable) belongs to on debian-based distros
This revision to my command (command #8851) was called for when it failed to find the parent package of 'rlogin', which is really a deep symbolic link to /usr/bin/ssh. This revision fixes this newfound issue, while ensuring fixes of other older issues work too.

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" }

Writes ID3 tags using the file name as the title.
Assumes that the files are named as such: 01-Filename.mp3 If your files are named differently, change the number of periods in the sed 's/...\(.*\)/\1' bit to match the numbers of characters you need to cut off the front of the file. Note: This only writes the titles.

Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for: