CLI: Command History

CLI="Command Line Interface"

One of the most useful features of a modern shell like bash (although it did 'borrow' this feature from the old C shell), is the command history.

When you enter commands at the prompt, bash keeps a record of them, which you can see by entering:

history

See those numbers? If you want to run one of the commands, enter:

!N

where "N" is the number before it.

To find a command that you made, the best way (unless it was very recently used) is to use Ctrl-r (^R), and then enter the first letter or two. If it doesn't show up right away, hit ^R again until it does, or add the next letter.

When the right command shows up, just hit Enter.

^R is a backwards search through the history file.

^P and ^N move back and forwards through the history file from wherever you are. (up-down arrows will do the same thing)

^U and-or ^K will clear the prompt.

Needless to say, the history file can get really cluttered, and fortunately there are ways to keep the clutter down.

(history -c will delete every entry in the history file)

Put these in your ~-.bashrc:

export HISTCONTROL=ignorespace

export HISTIGNORE="ls:cd:&"

and have bash reread the file with:

source ~-.bashrc

HISTCONTROL=ignorespace

That means that any command you run that you don't want to be recorded in your history file can just be preceded by a space.

HISTIGNORE="ls:cd:&"

That's a list of patterns (you can use shell wildcards) that you want to be kept out of your history file. Short ones that you use all the time. The "&" means to ignore duplicates.

AC

-- alanconnor AT earthlink DOT net Use your real return address or I'll never know you ~