Handy Bash Snippets and Linux Tips

In my day-to-day work with Linux systems and development environments, I've collected a variety of useful command-line snippets and troubleshooting notes. This blog post shares some of my favorites from counting files to fixing display issues designed to boost your productivity and make your life easier.

1. Quickly Count Files in a Folder

fcount() { ls -1q "$1" | wc -l; }

Example:
fcount /home/nguyenlm/folder → 27

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2. Force Fix Broken CUDA Installation

sudo apt-get -o Dpkg::Options::="--force-overwrite" install --fix-broken

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3. Count Non-Blank Lines in a File

nbl-count() { grep -cve '^\s*$' "$1"; }

Example:
nbl-count file.txt → 10

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4. Run Docker Without Sudo

sudo chmod 666 /var/run/docker.sock

⚠️ Warning: This gives broad access to Docker socket. In production, add user to docker group instead.

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5. Fix Second Monitor Detection in Ubuntu

sudo apt-get purge 'nvidia*'
sudo add-apt-repository ppa:graphics-drivers
sudo apt-get update
sudo ubuntu-drivers autoinstall

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6. Fix “Invalid MIT-MAGIC-COOKIE-1” Error (JavaFX Display Issue)

First, check your active DISPLAY:

who
# Example: user :1 2017-10-12 21:58 (:1)

Set the correct environment:

export DISPLAY=:1.0
zenity --info --text "foobar"

Tip: Check .bashrc, .zshrc, /etc/environment, or desktop environment configs.

Reference: Arch Linux Forum

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7. Check Folder Size Quickly

sizeof() {
    du -h --max-depth=0 "$1"
}

Example:
sizeof BOOK → 895M BOOK/

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8. Sync Files from Local to Remote Using Rsync

rsync -aPz -e "ssh -p port" local_folder/ user@remote_host:remote_folder

Tip: Add -n for dry-run to preview changes.

Reference: Rsync Command in Linux - Linuxize

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9. Find and Kill Specific Processes

kill $(ps aux | grep '[p]rocess.py' | awk '{print $2}')

[p] prevents the grep command from appearing in the process list.

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10. Recover a Lost Tmux Session

pkill -USR1 tmux

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Final Thoughts

These snippets have saved me countless hours when working with Linux environments, machine learning servers, and production systems. Feel free to bookmark or adapt them to fit your own workflow! ⚡