Commands by ryrys (2)

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Group OR'd commands where you expect only one to work
Something to stuff in an alias when you are working in multiple environments. The double-pipe OR will fall through until one of the commands succeeds, and the rest won't be executed. Any STDERR will fall out, but the STDOUT from the correct command will bubble out of the parenthesis to the less command, or some other command you specify.

Turning off display
To turn off monitor: xset dpms force off To turn on, simply press a key, or move mouse/mousepad.

Access folder "-"
If you try to access cd - you go to the last folder you were in.

Delete All Objects From An S3 Bucket Using S3cmd

Get MX records for a domain
command is shorter, output unnecessary longer

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).

Count lines of source code excluding blank lines and comments
Much more accurate than other methods mentioned here straight out of the box.

Rename files in batch

kill all processes using a directory/file/etc
This command will kill all processes using a directory. It's quick and dirty. One may also use a -9 with kill in case regular kill doesn't work. This is useful if one needs to umount a directory.

List known debian vulnerabilities on your system -- many of which may not yet be patched.
You can search for CVEs at https://security-tracker.debian.org/tracker/ or use --report to get full links. This can be added to cron, but unless you're going to do manual patches, you'd just be torturing yourself.


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