Linux cheatsheet

Basic

• cd [directory] : change directory
• ls [directory] : list files & directories
  • -l : list
  • -a : all (hidden too)
  • -h : human sizes
• cp [src] [dst] : copy src to dst
  • -r : recursive (directory)
• rm [file or directory] : remove file or directory
  • -r : recursive (directory)
  • -f : force
• mkdir [directory] : create directory
  • -p : create parent directories as needed
• ln -s [target] [symlink] : create a symlink
• touch [file] : create empty file, mark file as newly edited
• source [file] : execute a .sh file within the current shell
• cat [file] : print file to the screen
• tree -a : print directory hierarchy
  • -a : show all files (hidden)
  • -L [max depth] : max depth
• tail -n [num of lines] [file] : show last N lines of a file
• file [file] : get file type
• stat [file] : get file info
• man [cmd] : show manual for cmd
• pwd : show current directory
• which [cmd] : show where cmd is located
• find : find files
  • find [directory] -name [file] : find file in directory
  • find [directory] -name *.[ext] : find all files of a given type
  • find [directory] -type f -exec grep "[text]" '{}' \; -print : find text in files

Permissions

• sudo [cmd] : run a cmd as root
• chmod [file] : change file permissions
  • -R : recursive
  • +x : make a file executable
  • +rw : make a file read-write
  • -w : make a file read-only
• chown [owner]:[group] [file] : change the owner of a file
• groups [user] : list groups of a user
• cat /etc/group : list all groups

Environment variables

• export [var]=[name] : set an env variable
• echo $[var] : print env variable
• echo $PATH : show system PATH
• export PATH=$PATH:[directory path] : add directory to system PATH
• echo "export PATH=$PATH:[directory path]" >> ~/.bashrc : change the system PATH permanently

Other

• ssh -p [port] [user]@[ip] : login to SSH
• scp [src path] [user]@[ip]:[dst path] : copy file to remote
  • -p [port] : specify port
  • -r : recursive (directory)
• scp [user]@[ip]:[src path] [dst path] : copy file from remote
• reboot : reboot system
• poweroff : shutdown system
• wget : ?
• tar -czvf [output file] [input dir] : create tar file (tar.gz)
• tar -xvf [input file] -C [output dir] : extract tar file
• zip : ?
• unzip : ?
• hexdump : dump file as hexa
• find . -name [file] | entr [cmd] : run a cmd whenever a file changes

Disk

• lsblk : list disk
• fdisk -l : disk info
• fdisk [disk] : partition disk
• mount [disk name] [directory] : mount disk
• umount [directory] : unmount disk
• cat /proc/mounts : mount info

Info

• fastfetch : system info
• uname -a : show kernel version
• lscpu : list CPU info
• lspci : list PCI devices (Bus:Device.Function)
  • -v : verbose
  • -vv : very verbose
  • -tv : tree
  • -k : kernel modules/drivers in use
  • -n : ID of PCI device (VendorID:deviceID)
• lsusb : list USB devices
  • -v : verbose
  • -t : tree
• nvidia-smi : show GPU info
• ifconfig : show network info
• iftop : list TCP sockets
• netstat -nat : list TCP sockets
• df -shc * | sort -rh : show disk usage
  • -s : summary
  • -h : human readable
  • -c : show total
  • -b : bytes
  • --apparent size
  • -d [max depth] : max depth
• free -h --si : show how much RAM
• htop : list process, kill process
• sensors : show temperature
• watch -t -n 1 "sensors | grep 'Core 0:'" : show CPU temperature
• nmap -Pn -p- -v [ip] : find open ports
• strace : trace syscalls
• cat /proc/[pid] : procfs, running processes
• cat /proc/meminfo : memory info
• cat /proc/cpuinfo : CPU info (CPUID)
• cat /proc/interrupts : interrupts in
• cat /proc/ioports : IO ports
• cat /proc/iomem : MMIO
• cat /proc/driver/nvidia/ : GPU info
• cat /proc/stat : all process stats
• cat /proc/[pid]/stat : process stats

Kernel

• lsmod : list kernel modules
  • also cat /proc/modules
• insmod [module].ko : install kernel module
• rmmod [module] : remove kernel module
• modinfo -F [info] [module]: get info about kernel module
• dmesg | tail -n 5 : show kernel log
• ls -l /dev : list device files
  • major, minor
• cat /proc/devices : list assigned device numbers
• mknod [device] c [major] [minor] : create character device
• rmnod [device]
• head -c 1 [file] : output the first byte of a file

Paths

• . : current directory
• .. : parent directory
• ~ : home directory
• ../relative/path : relative path
• /absolute/path : absolute path

Pipes

• A | B : run A and transfer its output to B
• A & B : run A then B
• A && B : run A then B only if A succeeds
• | grep [some string] : filter out stdout

Redirect

• > : stdout
• < : stdin
• &> : stdout + stderr
• 0> : stdin
• 1> : stdout
• 2> : stderr
• 2>&1 : stderr to stdout, can use cmd | tee out.txt to also print on screen

Bash profile

• ~/.bashrc
  • executed every new shell
• ~/.bash_profile
  • executed once per login
  • inherit ~/.bashrc

Filesystem

FSH

• /proc : procfs, running processes
• /dev : udev, devices files
• /sys : sysfs, devices/bus/drivers/kernel
  • /sys/bus/pci/devices

Fedora

DNF

• dnf search [package] : search for package in repos
• dnf info [package] : get info about package
• dnf install [package] : install package
• dnf remove [package] : remove package
• dnf erase [package] : remove package+deps+config (careful!)
• dnf list installed : list installed packages
• dnf list available : list all availables packages
• dnf list installed *pattern*: list packages with pattern
• dnf upgrade : upgrade/update all packages
  • -v : verbose
  • --exclude=kernel*,*nvidia* : exclude some packages
• dnf autoremove : remove unused packages
• dnf clean all : clear cached packages
• dnf history : show dnf history
• dnf repolist all : list repos
• dnf config-manager --add-repo [some_repo.repo] : add repo
• dnf config-manager --set-enabled [repo] : enable repo
• dnf config-manager --set-disabled [repo] : disable repo
• rm /etc/yum.repos.d/[repo] : remove repo
• dnf repository-packages [repo] list --installed : list all packages installed from specific repo
• dnf provides [file] : find package that provides a file
• dnf repoquery -l [package] : list files in package
• dnf repoquery --requires [package]: list dependencies of package
• dnf repoquery --whatrequires [package] : list packages that depends on a package

Services

• systemctl status [service] : get status of service
• systemctl enable [service] : enable service at boot
• systemctl disable [service] : disable service at boot
• systemctl start [service] : start service
• systemctl stop [service] : stop service
• systemctl restart [service] : restart service
• systemctl list-units : list services running

Python

• pip list : list installed python libs
• pip install --user [lib] : install python lib
• pip install --user -r requirements.txt : install all python libs in requirements file
• pipreqs requirements.txt : create requirements.txt for current project
• python -m http.server : run HTTP server

Virtual Environment (venv)

• python -m venv [venv] : create venv
• source [venv]/bin/activate : enable venv
• pip freeze > requirements.txt : create requirements.txt
• deactivate : disable venv
• rm -rf [venv] : remove venv

Debugger (pdb)

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