Stop leaving temp files behind when your scripts crash. Bash has a built-in cleanup hook.

Instead of:

tmpfile=$(mktemp)
# do stuff with $tmpfile
rm "$tmpfile"
# hope nothing failed before we got here

Just use:

cleanup() { rm -f "$tmpfile"; }
trap cleanup EXIT

tmpfile=$(mktemp)
# do stuff with $tmpfile

trap runs your function no matter how the script exits -- normal, error, Ctrl+C, kill. Your temp files always get cleaned up. No more orphaned junk in /tmp.

Real world:

# Lock file that always gets released
cleanup() { rm -f /var/run/myapp.lock; }
trap cleanup EXIT
touch /var/run/myapp.lock

# SSH tunnel that always gets torn down
cleanup() { kill "$tunnel_pid" 2>/dev/null; }
trap cleanup EXIT
ssh -fN -L 5432:db:5432 jumpbox &
tunnel_pid=$!

# Multiple things to clean up
cleanup() {
rm -f "$tmpfile" "$pidfile"
kill "$bg_pid" 2>/dev/null
}
trap cleanup EXIT

The trick is defining trap before creating the resources. If your script dies between mktemp and the rm at the bottom, the file stays. With trap at the top, it never does.

Works in bash, zsh, and POSIX sh. One of the few tricks that's actually portable.

https://redd.it/1rlrlom
@r_bash

hyprbole – a terminal UI for managing Hyprland config, written in bash

hi first project in a while
github:
https://github.com/vlensys/hyprbole
AUR:
https://aur.archlinux.org/packages/hyprbole

planning on getting it on more repositories soon

https://redd.it/1rlvq4n
@r_bash

Shuf && cp

Hello! Posting this question for the good people of Bash.
I'm making a text-based game on Bash for my little kid to learn through it, bashcrawl styled.
I have a folder with monsters and I want them to get randomly copied into my current directory.
I do ls <source> | shuf -n 2 ,thus orrectly displaying them when I run the script for choosing the monsters.

but i fail miserably when copying them in the directory in which I am. Tried using ' . ', $PWD , and dir1/* . ,plus basically every example I found on stack overflow, but to no avail. I keep on getting error messages. If I dont copy, I have them shuffled and displayed correctly.
Anyone here can throw me a line, would be of much help. Thank you!!

https://redd.it/1ror51z
@r_bash

Why was BASH script post removed?

I was posting about the script I created for use as a cron job to edit the hosts file.

It met all the rules, 1, 2, 3, and 4. I don't understand why it wasn't allowed.

I had a feeling the technique I used might not be best practice, but was hoping for feedback about it to learn why, or maybe there are solutions I wasn't aware (although I did list some noting my difficulties in comprehending them such that this solution was the easiest for me to get working).



https://redd.it/1rl4lxt
@r_bash

tinybar - A simple taskbar utility for multiple shell session management
https://redd.it/1rkjl0w
@r_bash

Wallpaper Changing script
https://redd.it/1rpe82i
@r_bash

Built yet another public IP lookup
https://redd.it/1rrco97
@r_bash

A simple, compact way to declare command dependencies

I wouldn't normally get excited at the thought of a shell script tracking its own dependencies, but this is a nice, compact pattern that also feels quite a bit like the usual dependency *import* mechanisms of more modern languages. There's a loose sense in which importing *is* what you're doing, essentially asking the system if you can pull in the requested command, and of course, as such, you're also documenting your required commands upfront.

declare -r SCRIPT_NAME="${0##*/}"

require() {
local -r dependency_name="$1"
local dependency_fqdn

if ! dependency_fqdn="$(command -v "$dependency_name" 2>/dev/null)"; then
echo "Error: dependency $dependency_name is not installed"
echo "$SCRIPT_NAME cannot run without this, exiting now"
exit 1
fi

printf -v "${dependency_name^^}_CMD" '%s' "$dependency_fqdn"
}

require pass
echo $PASS_CMD

The resulting variable assignment gives you a convenient way to pass around the full path of the command. It's a bit of magic at first blush, but I'd also argue it's nothing that a doc comment on the function couldn't clear up.

Just a cool trick that felt worth a share.

**EDIT:** swapped out `which` for `command`, a Bash builtin, per suggestion by /u/OneTurnMore.

https://redd.it/1rrdofl
@r_bash

I built a free Bash PS1 prompt generator — looking for Linux user feedback

Hi everyone, I built a small web tool to help generate custom Bash PS1 prompts visually.

You can add prompt elements (date/time, user, host, path, git info, symbols), style them with colors/text attributes, reorder them, and instantly copy the final prompt code.

I just published the first public release and I’d really appreciate feedback from Linux users:

* Is the generated output clean and practical for real shells?
* Which prompt elements are missing?
* Any UX issues or bugs on your distro/browser?

Project link: [https://neiki.eu/bash-prompt-generator/](https://neiki.eu/bash-prompt-generator/)
GitHub: [https://github.com/jindrichstoklasa/bash-prompt-generator](https://github.com/jindrichstoklasa/bash-prompt-generator)

Thanks — even short feedback is super helpful.

https://redd.it/1rr3eie
@r_bash

Parsing duf (partial) through to my ~/.bashrc
https://redd.it/1rrjutx
@r_bash

I built a custom AST-based shell interpreter in the browser. Looking for edge cases to break it.

https://redd.it/1rr1a2u
@r_bash

Beginner Question automate install pkgs

I'm install Termux fresh and have gathered a list of tools below which I want to feed into: pkg install <contents of list.txt> cleanly line by line or glob.
list.txt:

tldr
ncdu
python-pip
fzf
wget
curl
p7zip
tar
fd
ripgrep
rclone
nano
tmux
cava
cmatrix
zip
unzip
cmake
mplayer
nmap
make
pkg-config
nodejs
tcpdump
netcat-openbsd
yt-dlp
busybox
proot-distro
htop
eza
git
zellij
lolcat
fastfetch
bat
dua
rsync
starship
mpv
ffmpeg
dust
duf
bottom
neovim
procs
lazygit
tree
vim
openssh
clang
python

What's the proper syntax to pass to pkg install list.txt 📚

pkg install $(cat list.txt) correct?

https://redd.it/1rrohj7
@r_bash

Parsing both options and args with spaces on function

Hi!

I defined this function in my .bashrc:

function mytree {
    /usr/bin/tree -C $* | less -R -S
}

This works well so long as none of the arguments have spaces. If I quote the args string variable, "$* I can pass directories with spaces, but no further options; for example, if I use "$*, this fails: mytree -L 2 "/dir/with spaces". It tries to open /dir/with/ and spaces/.

Is there a way around this? I want to be able to pass options and dirs with spaces. Please refrain from suggesting I change a dir's name, I also use such functions at work and cannot do that on the servers.

Thanks!

https://redd.it/1rqwra5
@r_bash

bashd: Bash language server (LSP)
https://github.com/matkrin/bashd

https://redd.it/1rrqu2s
@r_bash

Stop holding the left arrow key to fix a typo. You've had fc the whole time.

# you just ran this
aws s3 sync /var/backups/prod s3://my-buket/prod --delete --exclude "*.tmp"
#                                      ^typo

Hold ← for ten seconds. Miss it. Hold again. Fix it. Run it. Wrong bucket. Rage.

Or:

fc

That's it. fc opens your last command in $EDITOR.Navigate directly to the typo, fix it, save and quit — the corrected command executes automatically.

Works in bash and zsh. Has been there since forever. You've just never needed to know the name.

Bonus: fc -l shows your recent history. fc -s old=new does inline substitution without opening an editor. But honestly, just fc alone is the one you'll use every week.

https://redd.it/1rpwcad
@r_bash

Depending on the client I use to Telnet or NCAT ascii.bigjobby.com 2323, I get different results. NCAT generally works as intended across clients but Telnet is sketchy, sometimes I get colour and sometimes I don't. Is colour via Telnet even possible or am I silently falling back to NCAT?



https://redd.it/1rqtx85
@r_bash

Neglected !! party tricks

Everybody knows about using !! to add sudo to your previous command, but there are a couple other things I constantly use it for. So this is just a little PSA in case it never occured to you:

1. grep results

Say I want to search a bunch of files for a string, and then open all files containing that string in my editor.

I want to check the search results first, and I never get the exact search correct on my first try anyway, so I'll run a series of commands that might look like...

grep -rn . -e "mystring"
...
grep -rn . -e "my.\?string"
...
grep -Rni . -e "my.\?string"
...

Checking the results each time, until I have exactly the set of files that I want.

Here's the trick: now add the "-l" flag to grep to get just the file paths:

grep -Rnil . -e "my.\?string"

Now when you use !!, you'll get all those filenames. Therefore we can just do vim -p $(!!) to get all those files opened in tabs in vim.

2. with which

Sometimes I want to read or edit a script that's on my computer.

To find it, I run which some-command. This confirms that it exists under that name, and that it's an actual script and not an alias or shell function.

Now, we can just use vim $(!!) or cat $(!!) or whatever to open it.

https://redd.it/1ry9vhm
@r_bash

How do you print "Here document" or "Here Strings" directly?

Edit (Solution): There are two solutions here, depending on the case in which you are.
- Case 1: You use Here Document to print some multiline text.
Don't do that.
Instead, you can just do this:

 printf "%s\r\n"\
  "This is the first line."\
  "This is the second line."

   # This solution has just one annoyance which is that you have to enclose all lines in double quotes and end with a slash.
    # But compare this to here documents which don't allow any special characters to be used, sort of.

- Case 2: You actually are getting some text from somewhere and you are wrapping it to make it a Here Document or something like that.
I would say that there is a high chance the first solution is still more optimal but if you don't feel that, the solution below is your hero.

Credit to: u/OnlyEntrepreneur4760, for reminding me that we can use \ to write a command in multiple lines.
Something I forgot since I consider it a bad habit and stopped using.
But it makes sense here.

---

 { printf "%s\n" "$(< /dev/stdin)"; } <<-EOF
  This is first line.
  This is second line.
  This is third line.
 EOF

Is this how everyone does it or is there a better way to print it directly without storing the "here document" or "here string" to a variable or a file?

PS: WITH ONLY USING BASH BUILTINS

https://redd.it/1rxvbpc
@r_bash