Commands by AlexanderPenny (0)

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Capture video of a linux desktop
Proper screencast with audio using ffmpeg and x264, as per http://verb3k.wordpress.com/2010/01/26/how-to-do-proper-screencasts-on-linux/

Print every Nth line
Sometimes commands give you too much feedback. Perhaps 1/100th might be enough. If so, every() is for you. $ my_verbose_command | every 100 will print every 100th line of output. Specifically, it will print lines 100, 200, 300, etc If you use a negative argument it will print the *first* of a block, $ my_verbose_command | every -100 It will print lines 1, 101, 201, 301, etc The function wraps up this useful sed snippet: $ ... | sed -n '0~100p' don't print anything by default $ sed -n starting at line 0, then every hundred lines ( ~100 ) print. $ '0~100p' There's also some bash magic to test if the number is negative: we want character 0, length 1, of variable N. $ ${N:0:1} If it *is* negative, strip off the first character ${N:1} is character 1 onwards (second actual character).

history autocompletion with arrow keys
This will enable the possibility to navigate in the history of the command you type with the arrow keys, example "na" and the arrow will give all command starting by na in the history.You can add these lines to your .bashrc (without &&) to use that in your default terminal.

Count lines in a file with grep
Returns the number of lines in a file, emulates "wc -l" behavior with grep.

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"

Smiley Face Bash Prompt
If your last command was a dud, your bash prompt will be angry at you. Otherwise it's happy. Soon you will crave its constant approval and your linux skills will improve simply to avoid low self-esteem.

Find the package that installed a command

Convert JSON to YAML
Convert JSON to YAML. Note that you'll need to have PyYaml installed.

Batch Convert SVG to PNG
Convert some SVG files into PNG using ImageMagick's convert command.

Have your sound card call out elapsed time.
Useful contexts : You are doing yoga or some other physical training in which you are holding a position. Or you practice the pomodoro productivity technique. Or your girlfriend said "We're leaving in 40 minutes". Design details: sleep executes before espeak to give you a 5 seconds head start. espeak is run in the background so it doesn't mess up the timing.

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