All notes
Linux terminal notes
- 1. Configuration
- 2. Compression and archives
- 3. Processes
- 4. Users
- 5. Groups
- 6. Permissions
- 7. Package management
- 8. Network
- 9. Systemd
- 10. Sound / speakers
- 11. Disks
- 12. Memory
- 13. GPU
- 14. Kernel
- 15. Clock
- 16. Environment variables
- 17. Job control
- 18. Cron
- 19. Cryptography
- 20. Text file manipulation
- 21. Tmux
- 22. Common commands
1. Configuration
/etc/default/* # Configs of OS boot services2. Compression and archives
tar -xf <arch.tar.gz> # Decompress and extract files
tar -cf <arch.tar> <file1> <file2> # Create archive
tar -caf <arch.tar.gz> <f1> <f2> # Compress and create archive
tar -tvf <arch.tar> # List content (verbosely)3. Processes
pidof <name> # Get PID(s) of process(es)
pidof -s <name> # Get single PID of process
pgrep -a <name> # List processes commands
ps aux | grep <name> # Find process by name
ps -fp $(pidof -s <name>) # Get process info by PID
kill -l # List all signals
kill -9 <PID> # Kill process4. Users
# /etc/passwd schema:
# username:password:UID:GID:comment:home:shell
w # Show who is logged in
last # Show last logged-in users
cat /etc/passwd # List all users
id <username> # Show user's info
adduser <username> # Add user
passwd <username> # Change user's password
usermod -l <new_name> <old_name> # Change username
userdel -r <username> # Delete user and home dir
su <username> # Switch to user
sudo <username> <command> # Exec command as other user5. Groups
# /etc/group schema:
# groupname:password:GID:group members
cat /etc/group # List all groups
groups <username> # List user's groups
usermod -aG <group> <username> # Add user to group
gpasswd -d <username <group> # Remove user from group6. Permissions
Permissions priority: User -> Group -> Other
ls -l # Check permissions
stat <file> # Info about access
chown <username> <file> # Change owner of <file>
chown <username>:<group> <file> # Change owner and group
chown -R <username> <dir> # Change dir and its content
chmod u=rwx,g=r,o= <file> # Change file permissions
chmod ug=rw <file> # Change file permissionss7. Package management
Repositories are defined in:
/etc/apt/sources.list.d//etc/apt/sources.list
apt update # Update local pkgs DB
apt list --upgradable # Show packages to be upgraded
apt install <pkg> # Install package
apt remove <pkg> --purge # Remove package
apt upgrade # Upgrade all packages
apt install <pkg> --only-upgrade # Upgrade one package
apt changelog <pkg> # Show pkg changelog
apt check # Check dependencies
apt-cache stats # Show pkgs stats
apt-cache search <pkg> # Search for pkg
apt-cache show <pkg> # Get pkg info
apt-cache policy <pkg> # Get pkg version info
apt autoclean # Clean cache
apt autoremove # Remove unnecessary pkgs
dpkg -i <pkg.deb> # Install pkg file
dpkg -l # List all installed pkgs
dpkg -L <pkg> # List files installed by pkg8. Network
ip a # Show network interfaces
ip link set <iface> down # Disable interface
ip link set <iface> up # Enable interface
ip link set <iface> <mode> on # Change interface mode
route # Show kernel routes
netstat -tlpn # Show open TCP ports
netstat
-a # Show listening and non-listening
-l # Show only listening
-n # Show IP instead of resolved name
-t # TCP only
-u # UDP only
-x # UNIX only
-p # PID with assigned socket
lsof -i # Show open network connections
# Create tunnel from rhost:rport to lhost:lport
ssh -L <lport>:<lhost>:<rport> <ruser>@<rhost> -fN 9. Systemd
systemctl list-unit-files # List all unit files
systemctl cat <service> # Show unit file
systemctl list-units # List all units
systemctl status <service> # Show service status
systemctl start <service> # Start service
systemctl stop <service> # Stop service
systemctl restart <service> # Restart service
systemctl enable <serivce> # Start service at boot
systemctl disable <serivce> # Stop service at boot
journalctl -u <service> # Show logs10. Sound / speakers
# With this tool you can set overall levels of sound card
alsamixer # ALSA driver mixer
> F6 # Select sound card
> ESC # Exit
alsactl store # Persist changes11. Disks
cfdisk # User-friendly partition tool
lsblk -fp # List disks with partitions
fdisk -l # List disks (low-level info)
df -hT # Show disk space
du <dir|file> -hs # Show size of file or dir12. Memory
free -h # Show memory stats
watch -n <secs> free -h # Show mem stats every N secs13. GPU
lspci -k | grep -EA3 'VGA|3D|Display' # List available GPUs
nvidia-smi # Nvidia GPU & driver info
nvidia-settings # GUI Nvidia settings14. Kernel
uname -a # Show current kernel version
dpkg -l | grep linux-image # List installed kernels15. Clock
timedatectl # Show OS datetime settings16. Environment variables
env # List all envs
printenv <env-name> # Print env value
export <name>=<value> # Set env
unset <env-name> # Unset env17. Job control
jobs # List all jobs
bg <id> # Place job in bg (running)
<command> & # Place job in bg (running)
fg <id> # Place job in fg
CTRL-Z # Stop job18. Cron
crontab -l # List cron entries
crontab -e # Edit cron entries19. Cryptography
openssl genrsa 2048 > rsa.key # Generate RSA key
ssh-keygen -t rsa -N "" # Generate RSA key-pair20. Text file manipulation
# Exclude lines present in both files and save them into :file-3
comm -3 <file-1> <file-2> > <file-3>21. Tmux
:new # New tab
ctrl + b ( # Previous tab
ctrl + b ) # Next tab22. Common commands
shutdown -r now # Reboot now
shutdown -P now # Shutdown now
uname -a # System info
hostnamectl # Host info
cat /etc/issue # Distro info
cat /etc/shells # All available shells
wget <URL> -O <file> # Download URL to <file>
wget -i <file> # Download URLs from <file>
find <dir> -name <file> # Find file/dir in <dir>
find <dir> -type d -name <dir> # Find directory
find <dir> -type f -name <dir> # Find file
find <dir> -empty # Find empty file/dir
find <dir> -name "*.txt" # Find .txt files
find <dir> -user <user> # Find <user> files
find <dir> -group <group> # Find <group> files
mkdir -p dir1/dir2/dir3 # Create nested dirs
ln -s <original> <link> # Create soft symbolic link
wc -l <file> # Count lines
grep -- "-v" # Grep dash pattern
grep -n <str> # Grep line numbers
grep -C5 <str> # Show 5 lines before and after
sensors # Show temperatures components