Commands tagged bash (821)

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shell function which allows you to tag files by creating symbolic links directories in a 'tags' folder.
shell function which allows you to tag files by creating symbolic links directories in a 'tags' folder. The tag function takes a tag name as its first argument, then a list of files which take that tag. The directory $HOME/tags/tagname will then hold symbolic links to each of the tagged files. This function was modified from bartonski's (http://www.commandlinefu.com/commands/view/10216) inspired by tmsu (found at https://bitbucket.org/oniony/tmsu/wiki/Home) with readlink function by flxndn (http://www.commandlinefu.com/commands/view/10222). Example: $ tag dog airedale.txt .shizturc weimeraner.pl This will create $HOME/tags/dog which contains symbolic links to airedale.txt .shizturc and weimeraner.pl

tee to a file descriptor
the tee command does fine with file names, but not so much with file descriptors, such as &2 (stderr). This uses process redirection to tee to the specified descriptor. In the sample output, it's being used to tee to stderr, which is connected with the terminal, and to wc -l, which is also outputting to the terminal. The result is the output of bash --version followed by the linecount

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

Maximum PNG compression with optipng, advpng, and advdef
optipng and advancecomp (for the the advpng and advdef tools) are the best FOSS tools for losslessly compressing PNGs. With the above tool chain, you can cut off as much as 20% off a PNG's file size.

list files recursively by size

list all opened ports on host
in loop, until the last port (65535), list all opened ports on host. in the sample I used localhost, but you can replace with any host to test.

How to run a command on a list of remote servers read from a file
dsh - Distributed shell, or dancer?s shell ;-) you can put your servers into /etc/dsh/machines.list than you don't have to serperate them by commata or group them in different files and only run commands for this groups dsh -M -c -a -- "apt-get update"

grep expression (perl regex) to extract all ip addresses from both ip and ifconfig commands output
It uses the following GNU grep options: "-o" which shows only the matching part of the line and "-P" which allows the use of Perl regular expressions.

Extract audio from Mythtv recording to Rockbox iPod using ffmpeg
There are some pretty good live performances on late night TV. With Mythtv I record David Letterman, Jimmy Fallon, and Conan nightly all in HD from over the air broadcasts. If I find a live performance I like I copy it to my Rockboxed iPod using this command. The Rockbox firmware knows how to downmix 5.1 audio. The command above extracts the audio from the video starting at 58 minutes and 15 seconds. It ends at the end of the file since this was the last performance of the recording. The command creates an ac3 file. I copy the ac3 file to my Rockbox iPod and rock on.

Binary search/replace
Replace all instances of "A" with "B" in file "source" saved as file "destination". !! IF A/B is multi-byte, then separate bytes with spaces like so: "s/20\ 0A/00/g".


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