(How) Is it possible to ‘save’ a command that I regularly (with a small change) need to enter at the prompt, permanently in GNOME Terminal so that I don’t need to type the command every time when it’s needed and it’s still there after a shutdown or restart?
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By default this is already being done. The feature you want to research is called history.
A web search for “bash history” lead me to this page: https://www.howtogeek.com/44997/how-to-use-bash-history-to-improve-your-command-line-productivity/
Hello @coffee ,
You could also look at installing fzf since it is a very handy fuzzy search tool for commandline history. Also, not as a self plug, but I wrote a Bash Article for Fedora Magazine Customizing Bash - Fedora Magazine it does have some good info about Bash basics.
Ctrl + R will bring up recent history, so you can call back previous commands. Some people use fzf to have a more interactive prompt and other nice interactions.
I’m more interested in wether or not you would like to create a program, or have some other type of interaction. If you could be more specific, we could have other solutions more comfortable for you.
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It’s not a big deal like a programme… It’s only about that I don’t need to type the same command every time.
When I press Ctrl + R, I get (reverse-i-search)':` as a new prompt. How do I go on to display the command I recently executed and that I’m looking for?
In addition to the shell history suggestions above, there are two other things you can do:
Bash aliases
I didn’t want temporary memory-backed filesystems showing up in the output of the df “disk free” command. Adding -x tmpfs -x devtmpfs' hides these. But that’s annoying to type every time. I also want to see the filesystem type -T, skip network filesystems -l, and have the output use “human friendly” units -h. To make this easy, I put the following into the file ~/.bashrc (which you should find already exists in your home directory):[1]
alias df='df -Tlh -x tmpfs -x devtmpfs'
Now, when I type df at the command prompt, the whole extended command is actually used. (To ignore any aliases and use the original command, prefix with \ — that is, literally enter \df instead of df as your command.)
The alias name doesn’t have to match an existing command — it could be diskfree or whatever.
Note that you’ll have to reload ~/.bashrc to make this take effect.
Write a shell script
This might sound intimidating, but … at the most basic level, it’s really accessible, because a shell script is just a list of commands.
- Create a regular text file (in
nano,vim, VScode, GNOME Text editor, whatever) - At the top of the file, put
#!/bin/bash, which is a “magic” incandation which tells the Linux kernel that this file is to be processed by the bash shell.[2] - Save the file somewhere in your
PATH—~/.local/bin/is a common location these days. You can name it whatever you want (for example,~/.local/bin/myscript). Ending with.shis common, but not necessary (because it’s those magic bytes that really matter). - Mark the file executable, like this:
chmod +x ~/.local/bin/myscript - Now, just run
myscript, and … there you go!
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Just start typing. The last command that contains the letters you typed will be filled in. You can then continue to press Ctrl + R to search the history backwards. When you find what you’re looking for, you can press Enter to execute the command or the → (Right Arrow key) to print it to the prompt and modify it further.
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I have already seen the command I was looking for so I know it exists but now it says (failed reverse-i-search). Does it perhaps search from back to front and when it reaches the beginning, it doesn’t continue searching from the end? How can the command be displayed again?
reverse-search-history is an incremental search, but not iterating through history. If I miss the command I’m looking for (which happens to me often), I just press Ctr + C to cancel the current search and then start over.
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I can’t find the command anymore. Is it possible when I found the command before and printed it to the default prompt with → (Right Arrow key) and then deleted the command line with either the Backspace or the Delete key, that this deleted it from the reverse-search-history, too?
The reverse-search-history command sets the region to the matched text and activates the mark.
Hitting Enter accepts the line regardless of where the cursor is. If this line is non-empty, add it to the history list. If this line is a modified history line, then restore the history line to its original state.
I pressed Ctrl + R at the default prompt ($), (reverse-i-search)‘: was displayed and I pressed Ctrl + R a few times. Then I found the command I was looking for. I pressed the → (Right Arrow key) to print it to the prompt ($). After that I deleted the command line by pressing Backspace and/or Delete. As I pressed Ctrl + R again, I couldn’t find the command (that I previously found) anymore at (reverse-i-search)’:. What’s the reason for this?
I strongly think you should try fzf sudo dnf install fzf since it gives you a way to search your command history with regex if you want or partial command names even, then retrieves a list of command line history items that meet the search criteria you entered. It’s much easier than what you seem to be going through atm.
A good read about setting up fzf on redhat or fedora … https://www.redhat.com/sysadmin/fzf-linux-fuzzy-finder
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It seems to be the way that history works — you are actually inserting a blank line in place of the deleted command in the current history list. The same applies if you use the up/down keys to scroll through the history.
However, when you close the current Bash session and open a new one, the missing command is appended to the history file and is available again.
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Don’t get me started on fzf usefulness ! 
I agree, fzf, eza and bat are a must set of commandline tools.
That’s right.
Just as a quick aside to this conversation :
Having
PROMPT_COMMAND="${PROMPT_COMMAND:+$PROMPT_COMMAND$'\n'}history -a; history -c; history -r"
inside of your .basrc file will help you, if you decide to use more than 1 Terminal while you work. The commands will be saved across sessions, and you will not lose any previously entered commands from other Terminals open.
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