Charly's Column – Shell History
Charly's Column – Shell History
For admins like Charly, who try to avoid typing at all costs, the shell offers an excellent opportunity to avoid wear on your fingertips in the form of built-in history.
There are commands that I type several dozen times a day – grep <something> /var/log/syslog
is such a classic. The shell keeps a history of all my entries; thanks to the history
command, I can always see in a numbered list which commands I typed last.
The history
command is not a separate tool; typing which history
at the command line just drops you into a black hole. Instead, history
is a part of the shell, a built-in keyword. history
's killer feature, for which lazy people like me are eternally grateful, is the interactive search. You enable it with Ctrl+R, changing the command-line prompt to (reverse-i-search)`':
.
If you start typing now, for example, the word net, the shell will show you the last command typed containing net. When you press Ctrl+R again, the history feature shows you an increasing number of older commands that contain net (Figure 1).
There are a number of other ways to execute commands stored in the history one more time. To repeat just the last command entered, you can do any of the following:
- Press the up arrow
- Press Ctrl+P ("previous" on keyboards without arrow keys)
- Type
!!
- Type
!-1
Sometimes using relative addressing backwards through history proves helpful. In the example from Figure 2, I reran the third-to-last command from the history by typing !-3
. If you wanted to repeat the last command that started with echo, you would just need to type !echo
.
You can also access the parameters from previous commands. If you just typed ls .bashrc
, you can enter vim !!:$
to open .bashrc
in the editor. If you have a command that requires root privileges, sudo !!
does the trick. In the meantime, I defined but
as an alias (Figure 3).
Occasionally, however, I find the history's length problematic, as it only stores 1,000 entries on my test system. This is not enough for me, so I added a HISTSIZE=10000
line to the /.bashrc
file to multiply the history size by 10. I also added HISTCONTROL=erasedups
to /.bashrc
. This means that the history
command, which I type several times, is only saved once – this saves space and gives a better overview.
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you've found an article to be beneficial.
News
-
PipeWire 1.0 Officially Released
PipeWire was created to take the place of the oft-troubled PulseAudio and has finally reached the 1.0 status as a major update with plenty of improvements and the usual bug fixes.
-
Rocky Linux 9.3 is Available for Download
The latest version of the RHEL alternative is now available and brings back cloud and container images for ppc64le along with plenty of new features and fixes.
-
Ubuntu Budgie Shifts How to Tackle Wayland
Ubuntu Budgie has yet to make the switch to Wayland but with a change in approaches, they're finally on track to making it happen.
-
TUXEDO's New Ultraportable Linux Workstation Released
The TUXEDO Pulse 14 blends portability with power, thanks to the AMD Ryzen 7 7840HS CPU.
-
AlmaLinux Will No Longer Be "Just Another RHEL Clone"
With the release of AlmaLinux 9.3, the distribution will be built entirely from upstream sources.
-
elementary OS 8 Has a Big Surprise in Store
When elementary OS 8 finally arrives, it will not only be based on Ubuntu 24.04 but it will also default to Wayland for better performance and security.
-
OpenELA Releases Enterprise Linux Source Code
With Red Hat restricting the source for RHEL, it was only a matter of time before those who depended on that source struck out on their own.
-
StripedFly Malware Hiding in Plain Sight as a Cryptocurrency Miner
A rather deceptive piece of malware has infected 1 million Windows and Linux hosts since 2017.
-
Experimental Wayland Support Planned for Linux Mint 21.3
As with most Linux distributions, the migration to Wayland is in full force. While some distributions have already made the move, Linux Mint has been a bit slower to do so.
-
Window Maker Live 0.96.0-0 Released
If you're a fan of the Window Maker window manager, there's a new official release of the Linux distribution that champions the old-school user interface.