# BASH HISTORY SEARCH AND REPLACE
      ^string1^string2^ Quick substitution. Repeat the last command, replacing string1 with
      string2. Equivalent to ``!!:s/string1/string2/''

# MORE BASH COMMAND LINE TRICKERY (messing with the history)
make a directory then move into it:
mkdir cgi-bin; cd !#$ 
!#$ is shorthand for "the first word of this command". If I wanted to pick the third word
out of the previous command, that would be: !!:3 (don't forget there is a zeroth word).

# execute the most recent command the contains the following string: 
!?string

# globally search replace on the previous line:
!!:gs/old/new/

# HEADS AND TAILS
ever wanted to copy a few files in the same directory, all of which have same 
long prefix, like: cp /usr/local/etc/apache/file1.txt /usr/local/etc/apache/file2.txt
you can grap and reuse that prefix. It's named !#:1:h like:
cp /usr/local/etc/apache/file1.txt !#:1:h/file2.txt !#:1:h/file3.txt


# SAVING A COMMAND WITHOUT EXECUTING
While using bash, if you have typed a long command, and then realize you don't want to execute it yet, don't delete it. Simply
append a # to the beginning of the line, and then hit enter. Bash will not execute the command, but will store it in history so later
you can go back, remove the # from the front, and execute it. 

# GOING FORWARD A BACK A WORD
META-F goes forward a word
META-B goes backward a word

# COMPARE A FILE WITH IT'S VARIOUS VERSIONS IN THE SAME DIRECTORY
diff file.*

# EXAMPLE of a basic command line script
% for f in `ls | grep -v ".sh"`; { mv ${f} ${f}.sh } 

# searching the history
Cntrl-R starts a reverse incremental search 

# Keyboard shortcuts: 
CTRL-k: delete ('kill') from cursor position to the end of the line
*	CTRL-u: delete from cursor position to the beginning of the line
*	ALT-d: delete from cursor position to the end of the current 'word'
*	CTRL-w: delete from cursor position to the beginning of the current 'word'
*	CTRL-a: move cursor to the first character of the line
*	CTRL-e: move cursor beyond the last character of the line
*	ALT-a: move cursor to the first character of the current 'word'
*	ALT-e: move cursor to the last character of the current 'word'
*	CTRL-y: insert latest deleted 'word'
*	ESC-_ or !$: repeats the last argument of the previous command.
Example: You created a directory with mkdir /usr/local/bin/peter/pan. Now you want to change into that directory with cd. Instead of typing the path again, you type cd ESC-_ or

# Diff 2 files with a common base:
diff {alpha,beta}site/config/Config.pl