Commands tagged bash tricks

For those files in current folder that would be shown in `ls *ext`, for some extension ext, move/rename that file removing the .ext suffix from the file name.

It uses Bash's parameter substitution, as seen in

http://tldp.org/LDP/abs/html/parameter-substitution.html#PCTPATREF

(for analog use in prefix, see http://tldp.org/LDP/abs/html/parameter-substitution.html#PSOREX2 )

Can be used for command line parameters too.

If you have a more complicated way of entering values (validation, GUI, ...), then write a function i.e. EnterValue() that echoes the value and then you can write:

The biggest advantage of this over the functions is that it is portable.

Actually $! is an internal variable containing PID of the last job in background.

More info: http://tldp.org/LDP/abs/html/internalvariables.html#PIDVARREF

Using $! for job control:

After executing a command with multiple arguments like

cp ./temp/test.sh ~/prog/ifdown.sh

you can paste any argument of the previous command to the console, like

ls -l ALT+1+.

is equivalent to

ls -l ./temp/test.sh

ALT+0+. stands for command itself ('ls' in this case)

Simple ALT+. cycles through last arguments of previous commands.

Tested with bash v4.1.5 on ubuntu 10.10

Limitations:

as written above, only works for programs with no file extention (i.e 'proggy', but not 'proggy.sh')

because \eb maps to readine function backward-word rather then shell-backward-word (which

is unbinded by default on ubuntu), and correspondingly for \ef.

if you're willing to have Ctrl-f and Ctrl-g taken up too , you can insert the following lines

into ~/.inputrc, in which case invoking Ctrl-e will do the right thing both for "proggy" and "proggy.sh".

-- cut here --

\C-f:shell-backward-word

\C-g:shell-forward-word

"\C-e":"\C-f`which \C-g`\e\C-e"

-- cut here --

Use this BASH trick to create a variable containing the TAB character and pass it as the argument to sort, join, cut and other commands which don't understand the \t notation.

hit BACKSPACE more than once to delete more words

for example if you did a:

then

is equivalent to doing a

combines mkdir and cd

added quotes around $_, thanx to flatcap!

With counter format [001, 002, ..., 999] , nice with pictures or wallpapers collections.

This should work on any unix platform running bash. Just type the program into cat and give it a ^D when you're done, at which time it will compile, run, and remove the program. Obviously, you can run it without the "rm a.out" if you'd like to keep the binary. If you want to keep the source, well, you might as well just write it in vi or emacs first then.

How often do you make a directory (or series of directories) and then change into it to do whatever? 99% of the time that is what I do.

This BASH function 'md' will make the directory path then immediately change to the new directory. By using the 'mkdir -p' switch, the intermediate directories are created as well if they do not exist.

Searches backwards through your command-history for the typed text. Repeatedly hitting Ctrl-R will search progressively further. Return invokes the command.

Uses the last argument of the last executed command, and gets the directory name from it.

Use $!:t for the filename alone, without the dirname.

Yes, it's useless.

Useful for use in other scripts for renaming, testing for extensions, etc.