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There are a lot of common commands we use on the command line whose names or standard arguments can be difficult to remember. What are some good mnemonics that can be used to remedy this problem?

Example: a good mnemonic I've found for decompressing tarballs (tar xzf) is extract ze files!

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migrated from May 30 '11 at 0:19

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tar xzf would probably be better remembered as extract zlib from file, that way when you get a .tar that isn't compressed, it is easier to remember to leave off the z, or if you're working with tapes you'll know to leave off the f, since it isn't coming from a file. :) – sarnold May 30 '11 at 0:16
I voted to actual close rather than migrate and if I could vote to close here I would do so. This particular question indicates pretty bad understanding of the fundamentals. – Joshua May 30 '11 at 0:20
@Joshua: How so? "Understanding of the fundamentals" imbues one with superhuman memory now? – Lightness Races in Orbit May 30 '11 at 0:22
@sarnold: You are correct, but I prefer to imagine my mnemonics with a funny german accent. – Damien Wilson May 30 '11 at 0:29
Agreed. Mnemonics are a great way to remember things, even if you're a pro. A lot of commands have weird names or weird arguments, it can be much easier to remember a mnemonic device than the actual meaning. – jcrawfordor May 30 '11 at 0:29

Alt-SysRq-R+E+I+S+U+B -- Reboot Even If System Utterly Broken

This is the only one you need in a pinch. <plug>For everything else, there's StackExchange.</plug>

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I can appreciate this one; god knows I break plenty of systems. – Damien Wilson May 31 '11 at 5:23
The reality is I haven't gotten magic SysRq to do anything when my system has hung, not even once. It's disabled on many popular distributions by default and it's kind of late to turn it on when you need it. Plus if you're using a USB keyboard it may or may not work in the first place. – Matti Virkkunen Jan 19 '15 at 12:28

Most utilities without a ton of switches are developed with memorization in mind to a certain extent. Of course, when there are utilities with 100+ switches developers are forced to improvise with long-named switches (e.g --version ) which make this kind of thing even easier.

Some mnemonics that are handy:

tar xzf file... -- extract (g)zipped file.

ls -laR -- list all recursively

rm -rf -- remove recursively, force (cp and mv share many switches with rm)

mount -uw /mountpoint -- upgrade to writeable

sort -nr -- sort numbers in reverse

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