Commands by mathias (5)

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list all file extensions in a directory
If your grep doesn't have an -o option, you can use sed instead.

Simple colourized JSON formatting for BASH
Leave out pygmentize or `pip install pygments` first.

Quick searching with less

File rotation without rename command
Rotates log files with "gz"-extension in a directory for 7 days and enumerates the number in file name. i.e.: logfile.1.gz > logfile.2.gz I needed this line due to the limitations on AIX Unix systems which do not ship with the rename command.

Rename files in batch

Concatenate video files to YouTube ready output
Takes two input video files and an external audio track and encodes them together to an MPEG-4 DivX output video file with the correct size ready for uploading.

Write comments to your history.
A null operation with the name 'comment', allowing comments to be written to HISTFILE. Prepending '#' to a command will *not* write the command to the history file, although it will be available for the current session, thus '#' is not useful for keeping track of comments past the current session.

eth-tool summary of eth# devices
Give the Speed and Link status of eth# 0-3. This is sort of what mii-tool does, but eth-tool is better, yet lacks device discovery.

Get all these commands in a text file with description.
I tried out on my Mac, jot to generate sequence ( 0,25,50,..), you can use 'seq' if it is linux to generate numbers, need curl installed on the machine, then it rocks. @Satya

Count the total amount of hours of your music collection
First the find command finds all files in your current directory (.). This is piped to xargs to be able to run the next shell pipeline in parallel. The xargs -P argument specifies how many processes you want to run in parallel, you can set this higher than your core count as the duration reading is mainly IO bound. The -print0 and -0 arguments of find and xargs respectively are used to easily handle files with spaces or other special characters. A subshell is executed by xargs to have a shell pipeline for each file that is found by find. This pipeline extracts the duration and converts it to a format easily parsed by awk. ffmpeg reads the file and prints a lot of information about it, grep extracts the duration line. cut and sed cut out the time information, and tr converts the last . to a : to make it easier to split by awk. awk is a specialized programming language for use in shell scripts. Here we use it to split the time elements in 4 variables and add them up.


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