Commands tagged wikipedia (6)

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Runs previous command replacing foo by bar every time that foo appears
To replace foo by bar, but not execute, do ^foo^bar^:p To replace all foo by bar, but not execute, do ^foo^bar^:&:p

List processes playing sound
When trying to play a sound you may sometimes get an error saying that your sound card is already used, but not by what process. This will list all processes playing sound, useful to kill processes that you no longer need but that keep using your sound card.

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

Create a backup copy of a MySQL database on the same host
This should probably only be used for testing in a dev environment as it's not terribly efficient, but if you're doing something that might trash a DB and you still want the old data available, this works like a charm.

watch process stack, sampled at 1s intervals
This command repeatedly gets the specified process' stack using pstack (which is an insanely clever and tiny wrapper for gdb) and displays it fullscreen. Since it updates every second, you rapidly get an idea of where your program is stuck or spending time. The 'tac' is used to make the output grow down, which makes it less jumpy. If the output is too big for your screen, you can always leave the 'tac' off to see the inner calls. (Or, better yet--get a bigger screen.) Caveats: Won't work with stripped binaries and probably not well with threads, but you don't want to strip your binaries or use threads anyway.

list files recursively by size

list files recursively by size

ls -qahlSr # list all files in size order - largest last
I find it useful, when cleaning up deleting unwanted files to make more space, to list in size order so I can delete the largest first. Note that using "q" shows files with non-printing characters in name. In this sample output (above), I found two copies of the same iso file both of which are immediate "delete candidates" for me.

Show me just the ip address
Sometimes it's useful to output just the ip address. Or some other information, changing the "ipv4.addresses" in command. The power of awk! Show all possible "greps" with $ nmcli connection show [yourInterfaceNameHere]

Sets shell timeout
Useful in root's .profile - will auto-logout after TMOUT seconds of inactivity. Close after `seconds` inactive. export TMOUT=seconds (unefunge)


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