What is your single most favorite command-line trick using Bash? [closed]

Answer 1

String multiple commands together using the && command:

./run.sh && tail -f log.txt

or

kill -9 1111 && ./start.sh

Answer 2

I'm a fan of the !$, !^ and !* expandos, returning, from the most recent submitted command line: the last item, first non-command item, and all non-command items. To wit (Note that the shell prints out the command first):

$ echo foo bar baz
foo bar baz
$ echo bang-dollar: !$ bang-hat: !^ bang-star: !*
echo bang-dollar: baz bang-hat: foo bang-star: foo bar baz
bang-dollar: baz bang-hat: foo bang-star: foo bar baz

This comes in handy when you, say ls filea fileb, and want to edit one of them: vi !$ or both of them: vimdiff !*. It can also be generalized to "the nth argument" like so:

$ echo foo bar baz
$ echo !:2
echo bar
bar

Finally, with pathnames, you can get at parts of the path by appending :h and :t to any of the above expandos:

$ ls /usr/bin/id
/usr/bin/id
$ echo Head: !$:h  Tail: !$:t
echo Head: /usr/bin Tail: id
Head: /usr/bin Tail: id

Answer 3

pushd and popd almost always come in handy

Answer 4

My favorite is '^string^string2' which takes the last command, replaces string with string2 and executes it

$ ehco foo bar baz
bash: ehco: command not found
$ ^ehco^echo
foo bar baz

Bash command line history guide

Answer 5

I like to construct commands with echo and pipe them to the shell:

$ find dir -name \*~ | xargs echo rm
...
$ find dir -name \*~ | xargs echo rm | ksh -s

Why? Because it allows me to look at what's going to be done before I do it. That way if I have a horrible error (like removing my home directory), I can catch it before it happens. Obviously, this is most important for destructive or irrevocable actions.

Answer 6

I use the following a lot:

The :p modifier to print a history result. E.g.

!!:p

Will print the last command so you can check that it's correct before running it again. Just enter !! to execute it.

In a similar vein:

!?foo?:p

Will search your history for the most recent command that contained the string 'foo' and print it.

If you don't need to print,

!?foo

does the search and executes it straight away.