history (shows your last commands)
When using the command line on linux computers, you invariably end up typing
the same command many times. The
linux Bash shell keeps track of your
commands in a history file, which you can see by typing history:
$ history
... (potentially lots of commands)
5001 cd cs107/assignments/assign0
5002 ls
5003 cat hello.c
5004 ls
5005 cd
5006 ls
5007 ls -alrt
5008 history
$
There are many ways to retrieve commands from your history:
Up/Down arrow keys (redo a previous command): use the up arrow key to go back through your commands one at a time, and down to go the other way through the list
!character: if you type an exclamation point (also known as bang) followed by a character or a string and then enter, you will run the last command that starts with that character or string. E.g.,
$ ls -a
. .. hello hello.c hello.c~ innerFolder readme.txt samples
$ cd ..
$ !l
ls -a
. assign0 assign2 .do_not_look.txt file2.txt
.. assign1 assign3 file1.txt .this_is_hidden.txt
$
Typing !l runs ls -a again, because the previous command that started
with l was ls -a.
Ctrl-R: If you hold down the control key, and then type "r", you can then start typing characters and the line will start being populated with the last command that starts with the characters you have typed. This is easier to see in the Video and you should try it yourself. Back to contents