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Bash Shell Tricks

Bhaskar Karambelkar on July 09, 2017

This was originally published on my blog back in 2007, I am glad to see that this has aged well. I still find personally using many of the tricks m...

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Valentin Baca • Jul 13 '17 • Edited

Neat tips! thanks

Here's mine:

We all know !! but it's mostly just used to sudo !!
I find !$ (which is last argument of the last command) incredibly useful:

#make a directory and go to it
mkdir workspace
cd workspace

# OR even better
mkdir workspace
cd !$

# move then edit a file
mv ~/somefile.txt ~/renamed.txt
vim !$

# edited a file, now add it to git
vim awesome_code.c
git add !$

There's a whole slew of ! commands but !$ is one I use all the time.

Sébastien Larivière • Sep 1 '17

You can also use esc + . instead of !$. I find more natural and useful if you need to fix a typo.

Valentin Baca • Sep 1 '17

Even better! Thanks

P.S. For posterity, all of these work just as well in zsh.

Bhaskar Karambelkar • Jul 16 '17

Funny $_ is the exact same as !$. There's always more to learn 😀.

Geoff Davis • Jul 10 '17 • Edited

Great write-up!

Quick note, if you are using the command edit/replace feature and are using a conditional command construct (echo "first command" && echo "second command!") the ^foo^bar syntax only replaces the first instance of the searched text.

To replace every instance of that searched text, you have to use !!:gs/foo/bar; going back to my first example:

To replace all the instances of command in...

echo "first command" && echo "second command!"

...you have to execute...

!!:gs/command/echo

...to output:

first echo
second echo!

Further reading: Stack exchange

Bhaskar Karambelkar • Jul 11 '17

Yup I found out about it sometime after I wrote the original post almost 10 years ago. Thanks for the reminder!

Alexander Kashev • Sep 2 '17 • Edited

Small correction: bash completion for SSH looks for $HOME/.ssh/config, not authorized_keys

Bhaskar Karambelkar • Sep 5 '17

Yikes my bad. Actually it should be $HOME/.ssh/known_hosts file for auto completing host names. You won't find host names in $HOME/.ssh/config unless you've explicitly put them there, but every host you connect to gets saved in known_hosts by default.

Alexander Kashev • Sep 5 '17 • Edited

Yes, it does, but bash-completion does not read hosts from known_hosts - at least on my Ubuntu 16.04 machine.

It will, however, read both hostnames and host aliases from config.

jorin • Apr 22 '18

Nice writeup! I definitely have look more into /dev/*!

I learn something new that unix tools can do basically every day 😄 In case someone is interested, I try to share those findings on a separate Twitter account: twitter.com/qvlio