Linux / FreeBSD: Avoid bash history duplicate lines with HISTCONTROL

Linux / FreeBSD: Avoid bash history duplicate lines with HISTCONTROL

Please see previous article "How to increase bash history size in Linux" [url]/how-to-increase-bash-history-size-in-linux-t19491.html[/url] first.

Bash history, by default, is 500 lines long. Running the same command multiple times, consume multiple bash history entries. Example:

Code:

[user@linux ~]# one-command
-bash: one-command: command not found
[user@linux ~]# one-command
-bash: one-command: command not found
[user@linux ~]# one-command
-bash: one-command: command not found
[user@linux ~]# one-command
-bash: one-command: command not found
[user@linux ~]# one-command
-bash: one-command: command not found
[user@linux ~]# history | tail
  504  one-command
  505  one-command
  506  one-command
  507  one-command
  508  one-command
  509  history | tail

This is also inconvenient when searching through history (using CTRL+R) or shifting with up/down keys and the same command pops up every time.
To avoid duplicate lines in bash history use the following bash variable in /etc/profile.d/bash_hist.sh file:

Code:

export HISTCONTROL=ignoreboth:erasedups

And the result:

Code:

[user@linux ~]# two-command
-bash: two-command: command not found
[user@linux ~]# two-command
-bash: two-command: command not found
[user@linux ~]# two-command
-bash: two-command: command not found
[user@linux ~]# two-command
-bash: two-command: command not found
[user@linux ~]# history | tail
  503  one-command
  504  one-command
  505  one-command
  506  one-command
  507  one-command
  508  export HISTCONTROL=ignoreboth:erasedups
  509  two-command
  510  history | tail