Content

This page is a personal Linux command lookup sheet. It now also includes the older Linux blog notes.

Shell Basics

Basic Commands

man <command>: show the manual page for a command.
mv <src> <dst>: move a file or directory.
rm <path>: remove a file or directory.
cat <file>: print file content.
fg: resume a paused process in the foreground.
bg: continue a paused process in the background.
jobs: list jobs started from the current shell.
touch <file>: create an empty file or update its timestamp.
chmod +x <file>: make a file executable.

Shell Tips

Use * to match multiple characters and ? to match one character.
Ctrl+D: exit the shell.
Ctrl+Z: suspend the current foreground process.
echo "content" > file: overwrite a file.
echo "content" >> file: append to a file.
grep "pattern" file: search for a pattern.
sed -i "/pattern/d" file: delete matching lines in place.

Nano

Ctrl+X: exit.
Ctrl+G: open help.
Ctrl+K: cut a line.
Ctrl+U: paste a line.
Ctrl+W: search.
Ctrl+Y / Ctrl+V: previous / next page.
Ctrl+A / Ctrl+E: line start / line end.

Shell Scripting

# variables
echo "$VAR"
expr "$VAR1" + "$VAR2"
read VAR

# conditional
if [ condition ]; then
  echo "true"
else
  echo "false"
fi

# loop
for VAR in $LIST; do
  echo "$VAR"
done

Installation

Conda

conda create -n myenv python=3.8      # create a new env
conda remove -n myenv --all           # delete the whole env
conda create -n new_env --clone old_env
conda env update -f requirement.yml

PyTorch, Torchvision, Python

NVIDIA driver: open Software & Updates, then use the Additional Drivers tab.
Install torch / torchvision / torchaudio with a specific CUDA wheel index:

pip install torch torchvision torchaudio --extra-index-url https://download.pytorch.org/whl/cu128

Install a local wheel:

pip install package.whl

Temporary PyPI mirror:

pip install package_name -i https://pypi.tuna.tsinghua.edu.cn/simple

Global PyPI mirror:

pip config set global.index-url https://mirrors.cloud.tencent.com/pypi/simple

Venv

python3 -m venv venv
source venv/bin/activate
deactivate

AppImage

chmod a+x *.AppImage
./*.AppImage

Desktop Shortcut

Create a .desktop file under ~/.local/share/applications/:

[Desktop Entry]
Name=Another Redis Desktop
Comment=Another Redis Desktop
Exec=/opt/Another_Redis_Desktop/Another-Redis-Desktop-Manager.1.5.6.AppImage
Icon=/opt/Another_Redis_Desktop/ard.png
Terminal=false
Type=Application
Categories=Developer;

App Notes

Zotero: run ./set_launcher_icon, then link the generated desktop file:

ln -s /path/to/zotero/zotero.desktop ~/.local/share/applications/zotero.desktop

Zotero WebDAV can use Jianguoyun: https://dav.jianguoyun.com/dav/.
QQ Music sandbox workaround:

qqmusic --no-sandbox

System & Terminal

Supervise GPU usage:

watch -n 10 nvidia-smi

Look for proxy:

env | grep -i proxy

Check system architecture:

uname -m

Install / uninstall a .deb package:

sudo dpkg -i package_name.deb
sudo dpkg -r package_name

Show Python interpreter path:

import sys
path = sys.executable
print(path)

Set proxy in ~/.bashrc or ~/.zshrc, then source ~/.bashrc or source ~/.zshrc:

export https_proxy=http://proxy-host:port
export http_proxy=http://proxy-host:port

Unpack Files

cat event.tar.gz.part-* > event.tar.gz
tar -xvf archive.tar
tar -xzvf archive.tar.gz
tar -xjvf archive.tar.bz2
unzip archive.zip -d /path/to/directory
unrar e archive.rar

Download From URL

aria2c -s 10 -x 10 "URL"

-s is the split count, and -x is the number of connections per server.

Install / Uninstall Apps

sudo apt remove <package_name>  # remove app only
sudo apt purge <package_name>   # remove app and configuration files

Terminal Sessions

Nohup

Run a script in the background:

nohup /root/runoob.sh &

The output is written to nohup.out by default.

Find and kill the process:

ps -aux | grep "runoob.sh"
kill -9 <PID>

Tmux

vim ~/.tmux.conf
tmux source-file ~/.tmux.conf
tmux new -t session_name
tmux ls
tmux kill-window -t session_name

Detach window: Ctrl+B, then D.

Zellij

ctrl-p + d: create a pane below.
ctrl-p + r: create a pane on the right.
ctrl-p + x: close current pane.
ctrl-q: quit Zellij.

Python

python -c "print('Hello from command line')"
python -c "import torch; print(torch.cuda.is_available()); print(torch.__version__)"
python -m pip install package_name
python main.py -h

Docker

Docker installation and ROS container setup moved to Docker Setup.

Common commands:

docker images
docker rmi <REPOSITORY:TAG>
docker run --rm -it <IMAGE_ID> /bin/bash
docker ps
docker ps -a

Git

Basic Usage

git status
git add filename.txt
git add .
git commit -m "commit message"
git commit -am "commit message"
git push -u origin new_branch

Failure With Git Connection

If port 22 is blocked, use SSH over port 443:

text
Host github.com
    Hostname ssh.github.com
    Port 443
    User git

Put the block in ~/.ssh/config.

Set Username And Email

git config --global user.name "Tesla-SHT"
git config --global user.email "you@example.com"

For private repositories, use a username and PAT instead of a password.

Remote & Local Branch

Pull a remote branch to local:

git checkout -b branch origin/branch

Delete a local branch:

git checkout another_branch
git branch -D branch

Checkout, Switch, Restore

checkout can both move branches and restore files. switch and restore split those ideas more clearly.

# checkout
git checkout develop
git checkout -b new-feature
git checkout <commit-hash>
git checkout -- a.txt
git checkout HEAD -- a.txt

# switch
git switch develop
git switch -c new-feature
git switch -

# restore
git restore a.txt
git restore --staged a.txt
git restore --source=HEAD a.txt

Merge One Branch To Another

git pull --rebase: fetch remote commits and replay local commits after them.
git push: push current branch.
git checkout dev: switch to dev.
git merge main: merge main into dev.

Modify The Latest Commit

git reset --soft HEAD^
git reset --hard HEAD~1
git commit --amend

Use git reset --hard only when you intentionally want to discard local changes.

Submodule Tracking

Sometimes a submodule may not be tracked as expected.

Remove the original tracking:

git rm --cached <file-or-dir>

Delete the .git file in the submodule and delete the related file under the root .git directory if it exists.
git add the file again.

CUDA

Assign Process To GPU

CUDA_VISIBLE_DEVICES=0 python main.py
export CUDA_VISIBLE_DEVICES=0

import os
os.environ["CUDA_VISIBLE_DEVICES"] = "0"

import torch

torch.cuda.is_available()
torch.cuda.device_count()
torch.cuda.get_device_name(0)
torch.cuda.current_device()

VSCode

Python Interpreter

Ctrl+Shift+P: open command palette.
Choose Python: Select Interpreter.

Shortcuts

Ctrl+K Ctrl+S: open keyboard shortcuts.
Ctrl+Shift+F: global search.
Ctrl+P: quick open.
Ctrl+Shift+G: source control.
Ctrl+Shift+D: debug.
Ctrl+K M: select language mode.
Ctrl+Alt+N: run code with Code Runner.
Alt+Z: toggle word wrap.
Ctrl+Shift+P: command palette.

Regular Expression Table

Basic Syntax	Quantifiers	Position	Group	Common Usage
Any digit: `\d`	Zero or more: `*`	Start of line: `^`	`(abc)` group, use `$1` in replace	Empty line: `^\s*$`
Word character: `\w`	One or more: `+`	End of line: `$`	`[abc]` matches one of `a`, `b`, `c`	Comments: `//.*`
Whitespace: `\s`	Zero or one: `?`	Word boundary: `\b`	`a\|b` matches `a` or `b`	Quoted text: `"[^"]*"`
Any character: `.`	Exact count: `{n}`			Escape regex metacharacters such as dot, star, plus, question mark, brackets, pipe, and backslash.

Add SiliconFlow Model

Install an OAI-compatible extension.
Set the OAI base URL to https://api.siliconflow.cn/v1.
Add an OAI model in Copilot or Cline.

Desktop Environment

Xfce

If X server already running on display :0 appears, run:

exec startxfce4

Modify lockscreen time:

Section "ServerFlags"
    Option "BlankTime" "0"
    Option "StandbyTime" "0"
    Option "SuspendTime" "0"
    Option "OffTime" "0"
EndSection

Errors

Some Text Is Missing In GNOME

Restart GNOME Shell:

Press Alt+F2.
Type r.
Press Enter.

`dpkg: error: dpkg frontend lock is locked by another process`

ps -e | grep apt
sudo kill <PID>

Tesla

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