Home / ubuntu / Questions / 945335
Accepted
Old Geezer
Asked: 2017-08-12 06:18:13 +0800 CST

HISTCONTROL=ignoreboth doesn't work [duplicate]

  • 772

The default .bashrc in the standard distribution of Ubuntu 16.04 that comes with AWS has these lines:

# don't put duplicate lines or lines starting with space in the history.
# See bash(1) for more options
HISTCONTROL=ignoreboth

However, it doesn't seem to work. I have been running pm2 restart myApp and pm2 list repeatedly using the Up Arrow key, and the command buffer now contains nearly a hundred lines of these.

What could be wrong?

bash

1 Answers

  1. Best Answer

    It's working as intended. ignoredups, implied by ignoreboth, doesn't add a command to history if it's the same as the immediate previous command. It doesn't look further back in history. From the manual:

    A value of ‘ignoredups’ causes lines which match the previous history entry to not be saved.

    So, this will add foo twice to the history:

    $ foo
$ bar
$ foo

    But so will this:

    $ foo
$ bar
$ foo
$ foo

    The last foo won't be added to history, since the previous command was foo. Use erasedups in conjunction:

    A value of ‘erasedups’ causes all previous lines matching the current line to be removed from the history list before that line is saved.

    So:

    HISTCONTROL=ignoreboth:erasedups
    • 15