Bash/scripts

History functions

history  # display history for current tty
!!       # repeat last command
!foo     # repeat last command starting with 'foo'
!N       # execute command number N from history output
!foo:p   # _show_ last command starting with 'foo' but do _not_ execute it
!-N$:p   # _show_ N-commands ago but do _not_ execute it
!$       # grab last argument from previous command
!*       # grab all arguments from previous command
^F^f     # change first instance of "F" to "f" in last command (i.e., ^error^correction)

Command movements

Note: The carret ^ symbols means Ctrl+.

^w # erase word under cursor
^u # erase from here to beginning of the line
^a # move the cursor to the beginning of the line
^e # move the cursor to the end of the line

Brace expansion

Instead of doing this:

cp filename filename-old
cp filename-old filename

Try this:

cp filename{,-old}
cp filename{-old,}

• Create multiple files

touch a{1,2,3}b      # creates 'a1b', 'a2b', and 'a3b'
touch {f1,f2,f3,}o   # creates 'f1o', 'f2o', 'f3o', and 'o'

• List all files '/usr/bin/foo', '/usr/sbin/foo', '/usr/local/bin/foo', and '/usr/local/sbin/foo':

ls /usr/{,local/}{,s}bin/foo

Word modifiers

h # remove a trailing file name component, leaving only the head.
t # remove all leading file name components, leaving the tail.
r # remove a trailing suffix of the form .xxx, leaving the basename.
e # remove all but the trailing suffix.

• First list a file, then cd into its directory

ls -l foo/bar.txt
cd !$:h   # changes pwd to 'foo'

• Create a file and a directory as the basename of the file

touch foo.txt
mkdir !$:r  # creates a directory called 'foo' (without the .txt)

• Stacked word modifiers: Download a file to /tmp, and then create a directory for the contents of that tar file in /usr/local/src. Then extract the contents of the tarball into the newly created directory:

cd /tmp
wget http://www.example.com/path/SomePackageName.tar.gz
cd /usr/local/src/
mkdir !-2$:t:r:r      # creates a directory called 'SomePackageName'
cd !$                 # enter the above directory
tar xvzf /tmp/!-4$:t  # extract the contents of 'SomePackageName.tar.gz' here

• Substitution:

ls Foo         # file/directory does not exist, so:
!!:s/Foo/foo/  # change 'Foo' to 'foo' in last command

• Substitution (global):

ls Foo1; ls Foo2  # neither file/directory exist, so:
!!:gs/F/f/        # replace all 'F' with 'f' in previous command