bash: Clearing History
The excellent bash shell keeps a history of recently executed command lines and lets users cycle through them with up/down arrow, edit commands, and re-execute past commands.
Every once in a while, I make a mistake and type a password at a bash prompt — today it happened because I had a remote session waiting for a password, which timed out, so I typed my password at the “Password:” prompt, but my workstation noticed the connection was down and dropped me into bash, which failed to execute my password (because it’s of course not a valid command), and helpfully cached it on disk for future shells to take advantage of.
The quick fix is “history -c“, to flush the whole history (and Command-K in Terminal or whatever’s necessary in a different terminal program to clear the screen and scroll-back buffer).
A less drastic step is to use “history | tail” to find the line number of the bad command, and “history -d 503” (or whatever the appropriate line number is) to clear just the bad line, preserving the rest of the history. Further details are available with “man bash“.
Mistoffeles said,
December 21, 2006 at 2:12 pm
You can just type ‘history [n]‘ to get a list of the last n lines of the history, including the command numbers, for instance if you have a history with 12 commands and type ‘history 3′ you will get:
10 third last command 11 seond last command 12 last command