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bash tricks (sh.itjust.works)

submitted 3 days ago by zarkanian to c/[email protected]

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[–] [email protected] 6 points 3 days ago (1 children)

another useful one is <(cmd here)

It's like $(cmd here) but instead of returning the output of the command as a string passed into the arguments, it makes a new file descriptor for the output of the command and returns the path to it, for use in commands that want a file as an argument.

So for example if you want to use diff to compare your local passwd file to a remote one..

diff -u <(ssh host1 cat /etc/passwd) /etc/passwd

Admittedly I can't think of many things I've used this for outside of diff and alternatives to diff..but I've used it there a lot, like comparing the results of running two slightly different queries.

[–] [email protected] 4 points 3 days ago

I use this one for comm a lot. E.g.,

comm -12 <(sort some_file) <(grep foo some_other_file | sort)