Bash – .bash_history vs history command

bashcommand history

When I open my .bash_history file and view my previous commands via the history command, I see that they are not the same exact commands ?

I feel like the .bash_history commands contains less commands, is it because the .bash_history is updated every 24 hours or so ?

Also I wonder is there a limit for the number of commands to appear in my history or .bash_history file ?

Best Answer

What a particular process keeps in memory for the history will vary with what is in a history file depending on a variety of settings and commands, notably the HISTCONTROL, HISTFILE, HISTFILESIZE, HISTIGNORE, and HISTSIZE environment variables, and the fc and history commands, though the history section of the manual will doubtless make for better reading than this.

Related Solutions

Bash – Saving bash history from multiple Konsole not working correctly

I have concluded that it is not possible to append the new commands directly and at the same time to remove any duplicates. So my solution is to run the following command ones in a while. or to put it in my crontab.

tac $HOME/.bash_history | awk '!seen[$0]++' | tac > $HOME/.hist_Temp 
mv $HOME/.hist_Temp $HOME/.bash_history

The above command will keep the last occurrence of a command and remove every other repetitions above it from the history file without messing up the order.

Bash – How to sync terminal session command history in bash

Add this line to .bashrc:

export PROMPT_COMMAND="history -a; history -n"

Open new terminal and check.

Explanation

history -a appends new history lines to history file.
history -n tells bash to read lines that is not read from history file to current history list of session.
PROMPT_COMMAND: contents of this variable is run as regular command before bash show prompt. So every time after you execute a command, history -a; history -n is executed, and your bash history is synced.

Best Answer

Related Solutions

Bash – Saving bash history from multiple Konsole not working correctly

Bash – How to sync terminal session command history in bash

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