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

Question

We all know how to use `-R` to reverse search through history, but did you know you can use `-S` to forward search if you set `stty stop ""`? Also, have you ever tried running bind -p to see all of your keyboard shortcuts listed? There are over 455 on Mac OS X by default. What is your single most favorite obscure trick, keyboard shortcut or shopt configuration using bash?

Accepted Answer

When running commands, sometimes I'll want to run a command with the previous ones arguments. To do that, you can use this shortcut:

```
$ mkdir /tmp/new
$ cd !!:*
```

Occasionally, in lieu of using find, I'll break-out a one-line loop if I need to run a bunch of commands on a list of files.

```
for file in *.wav; do lame "$file" "$(basename "$file" .wav).mp3" ; done;
```

Configuring the command-line history options in my .bash_login (or .bashrc) is really useful. The following is a cadre of settings that I use on my Macbook Pro.

Setting the following makes bash erase duplicate commands in your history:

```
export HISTCONTROL="erasedups:ignoreboth"
```

I also jack my history size up pretty high too. Why not? It doesn't seem to slow anything down on today's microprocessors.

```
export HISTFILESIZE=500000
export HISTSIZE=100000
```

Another thing that I do is ignore some commands from my history. No need to remember the exit command.

```
export HISTIGNORE="&:[ ]*:exit"
```

You definitely want to set histappend. Otherwise, bash overwrites your history when you exit.

```
shopt -s histappend
```

Another option that I use is cmdhist. This lets you save multi-line commands to the history as one command.

```
shopt -s cmdhist
```

Finally, on Mac OS X (if you're not using vi mode), you'll want to reset <CTRL>-S from being scroll stop. This prevents bash from being able to interpret it as forward search.

```
stty stop ""
```

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

Solution

Problem