The more you work with linux terminals, the more you end up needing to optimize your recurring tasks, looking for commands that optimize your day-to-day and improve your productivity: The command history it sure is one of them. As the name already gives, the command history lists all the command history of your terminal (the same history can be found in the file .bash_history in your folder home ). By default, the command history displays the last 5k saved commands.
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Using the basic history command
just type history in the linux terminal to use the simplest mode of the command:
$history
# Result
1 clear
2 ls her
3 sudo apt-get update
4 history
The command history will display the command history of your session, at the beginning of each line there is a number, we can use this numbering to retrieve and re-execute the desired command:
$!2
# Result
drwxr-xr-x 2 shadowlik shadowlik 4096 Dec 28 17:40 Desktop
drwxr-xr-x 2 shadowlik shadowlik 4096 Dec 28 17:40 Documents
drwxr-xr-x 6 shadowlik shadowlik 4096 Jan 6 23:26 Downloads
There is another way to find and rerun commands by doing a generic search on the command history :
$!ls
You can also rerun your last command by typing !! .
Searching for a command using history
Now let's combine the command history with the command grep , so we'll be able to filter our history in search of the desired command:
$history | grep ls
# Result
2 sudo ls her
5 history | grep ls
Another way to access the search functionality is via the shortcut Ctrl-R . Type what you are looking for and your prompt will bring up the result:
(reverse-i-search)`':
Changing an executed command
We often want to find a command to rerun, but changing some option or parameter. The command history allows you to rerun commands with a different syntax. For example, if we want to change our previous command history | grep ls her for history | grep ls -ln , I can run the following command:
$^ls^ln^
THE history will rerun the command by swapping ls per ln .
Deleting the history
You may someday need to delete a command that contains some sensitive data or even all the commands in your history. To delete a particular command, type history -d <line#> and to erase the entire history content, type history -c .
