Linux Commands
Inhalt
Depending on the distribution, some commands may need to be installed first, e.g. whois
or dig
.
Commands can accept many more parameters than listed here. All available parameters can be taken from the help with man [COMMAND]
. The parameters can also be displayed with [COMMAND] --help
or [COMMAND] -h
.
Some commands or arguments require execution with the command sudo
.
Command Overview
Command | Description |
---|---|
!! | Execute the last command !!! |
> [FILE] | Create empty file !!! |
badblocks -s /dev/[DEVICE] | Drive check sudo |
cal | Shows current month calendar |
cat /etc/group | Shows all groups |
cat /etc/passwd | Shows all users |
cat /proc/cpuinfo | CPU information |
cat [FILE] | Output file content |
cat [SOURCE] >> [TARGET] | Append file content to another file |
cd .. | Go to parent directory |
cd [DIRECTORY] | Go to a directory |
cd ~ | Go to home directory |
chmod [RIGHTS] [FILE] | Change file permissions sudo !!! |
chown [USER] [FILE] | Change file owner sudo !!! |
chown [USER]:[GROUP] [FILE] | Change file owner and group sudo !!! |
cp -r [SOURCE] [DESTINATION] | Copy a directory |
cp [SOURCE] [DESTINATION] | Copy a file |
date | Shows current date and time |
date -R | Shows current date and time (RFC-5322) |
date -u | Shows current date and time (UTC) |
df -h | Shows free and used disk space |
dig [HOST] ANY | Show DNS information |
dmesg | Bootup messages sudo |
dmidecode | System information sudo |
dmidecode --dump-bin [FILE] | System information (dump to file) sudo |
dmidecode --from-dump [FILE] | System information (read from file) |
du -ah [PATH] | Shows disk usage |
exit | Exit the current shell |
fdisk -l | Shows partitions sudo !!! |
find [PATH] -name [EXPRESSION] | Search for files in a directory |
findmnt | List all file systems |
free -h | Memory usage |
gpg -c [FILE] | Encrypt a file |
gpg -d [FILE] | Decrypt a file |
grep -Hnir [TERM] [DIRECTORY] | Recursive search in a directory |
grep -i [TERM] [FILE] | Search in a file |
groupadd [GROUP] | Create new group sudo |
groupdel [GROUP] | Remove a group sudo !!! |
groups | Shows current groups |
gzip -d [FILE] | Decompress file with GNU ZIP |
gzip -k [FILE] | Compress file with GNU ZIP |
hdparm -g /dev/[DEVICE] | Drive geometry sudo !!! |
hdparm -i /dev/[DEVICE] | Drive information sudo !!! |
hdparm -tT /dev/[DEVICE] | Drive read-speed test sudo !!! |
head [FILE] | Shows the first 10 lines of a file |
hostname | Shows the system hostname |
hostname -i | Shows the system IP address |
id | Shows current user information |
id -un | Shows the own user name |
id [USER] | Shows user information |
ip addr | List IP addresses and network interfaces |
ip route | Shows routing table |
kill [PID] | Kill a process by its PID !!! |
killall [NAME] | Kill all processes with a given name |
last | Shows last logged in users |
last reboot | Shows system reboot history |
less [FILE] | Shows file content |
ln -s [TARGET] [NAME] | Create a symbolic link |
locate [TERM] | Search for files |
ls | List files in directory |
ls -la | List all files in directory |
lsblk | Block devices |
lsof | List all open files |
lspci | PCI devices |
lspci -tv | PCI devices (tree) |
lspci -v | PCI devices (verbose) |
lsusb | USB devices |
lsusb -tv | USB devices (tree) |
lsusb -v | USB devices (verbose) |
mkdir [DIRECTORY] | Create new directory |
more [FILE] | Shows file content |
mv [SOURCE] [DESTINATION] | Rename or move a file or directory !!! |
ping [HOST] | Ping a host |
pkill [NAME] | Kill a process by its name !!! |
pmap [PID] | Shows memory map o a process |
ps -aux | Shows all processes |
pstree | Shows processes (tree) |
pwd | Shows current directory path |
rm -r [DIRECTORY] | Remove directory !!! |
rm [FILE] | Remove file !!! |
ss -ap | Shows open ports |
tail [FILE] | Shows the last 10 lines of a file |
tar cf [TARGET] [FILES] | Compress files with TAR |
tar czf [TARGET] [FILES] | Compress files with TAR and GNU ZIP |
tar xf [FILE] | Extract files with TAR |
top | Shows processes (in real-time) |
touch [FILE] | Change file time !!! |
traceroute -I [HOST] | Trace route to a host |
uname -a | Shows system and kernel information |
uptime -p | Shows system running time |
uptime -s | Shows system start time |
useradd [USER] | Create new user sudo |
userdel [USER] | Remove user sudo !!! |
usermod -aG [GROUP] [USER] | Add a user to groups sudo !!! |
users | Shows logged in users |
w | Shows logged in users and their activity |
wc [FILE] | Count lines, words and bytes of a file |
who | Shows logged in users |
who -b | Shows system boot time |
whoami | Shows the own user name |
whois [HOST] | Get whois information |
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Commands by Category
Disks and Partitions
- df -h
- Shows the free and used space on all file systems.
- du -ah [PATH]
- Shows the disk usage for the specified [PATH]. Without a path, the current path is used.
- fdisk -l
- Lists all partitions, sizes and types.
Execute with sudo / Caution when using - findmnt
- Lists all file systems.
File Compression
- gzip -d [FILE]
- Decompresses a [FILE] with GNU ZIP.
- gzip -k [FILE]
- Compresses a [FILE] with GNU ZIP and store the compressed file as "[FILE].gz". Without the option "-k", the original file will be removed.
- tar cf [TARGET] [FILES]
- Compresses one or more [FILES] with TAR and store it as [TARGET] file (e.g. "archive.tar").
- tar czf [TARGET] [FILES]
- Compresses one or more [FILES] with TAR and GNU ZIP and store it as [TARGET] file (e.g. "archive.tar.gz").
- tar xf [FILE]
- Extracts files from a TAR [FILE].
File Permissions
- chmod [RIGHTS] [FILE]
- Changes the file permissions for a [FILE]. The [RIGHTS] can be entered as octal code (digits 0-7) in the order owner-group-others. Rights: 4=read, 2=write, 1=execute, 0=none. Examples: 777=all rights for all users, 644=read and write for owner, read only for all other.
Execute with sudo / Caution when using - chown [USER] [FILE]
- Changes the owner of the [FILE] to the specified [USER].
Execute with sudo / Caution when using - chown [USER]:[GROUP] [FILE]
- Changes the owner and the [GROUP] of the [FILE] to the specified [USER].
Execute with sudo / Caution when using
Files and Directories
- > [FILE]
- Creates a new empty [FILE]. If the [FILE] exists, it's size will be set to 0.
Caution when using - cat [FILE]
- Outputs the content of a [FILE].
- cat [SOURCE] >> [TARGET]
- Appends the content of one or more [SOURCE] files to a [TARGET] file.
- cp -r [SOURCE] [DESTINATION]
- Copies a [SOURCE] directory to a [DESTINATION] directory with its entire content.
- cp [SOURCE] [DESTINATION]
- Copies a [SOURCE] file to a [DESTINATION] file or directory.
- gpg -c [FILE]
- Encrypts a [FILE]. Password will be prompted.
- gpg -d [FILE]
- Decrypts a [FILE].
- head [FILE]
- Shows the first 10 lines of a [FILE].
- less [FILE]
- Shows the content of a [FILE]. Lines and/or pages are scrollable.
- ln -s [TARGET] [NAME]
- Creates a symbolic link with the given [NAME] to a [TARGET] file or directory.
- mkdir [DIRECTORY]
- Creates a new [DIRECTORY].
- more [FILE]
- Shows the content of a [FILE]. Lines and/or pages are scrollable.
- mv [SOURCE] [DESTINATION]
- Moves a [SOURCE] file or directory to a new [DESTINATION] or rename it.
Caution when using - pwd
- Prints full path of the current working directory.
- rm -r [DIRECTORY]
- Removes a [DIRECTORY] with its entire content.
Caution when using - rm [FILE]
- Removes the specified [FILE].
Caution when using - tail [FILE]
- Shows the last 10 lines of a [FILE].
- touch [FILE]
- Changes the access and modification time of a [FILE] to the current time. touch creates the [FILE], if it does not exist.
Caution when using - wc [FILE]
- Counts lines, words and bytes in the content of a [FILE].
Hardware
- badblocks -s /dev/[DEVICE]
- Checks a [DEVICE] for unreadable blocks.
Execute with sudo - cat /proc/cpuinfo
- Shows CPU information.
- dmesg
- Shows messages from system bootup.
Execute with sudo - dmidecode
- Shows information about BIOS, system, mainboard and chassis.
Execute with sudo - dmidecode --dump-bin [FILE]
- Dumps information about BIOS, system, mainboard and chassis in a binary file.
Execute with sudo - dmidecode --from-dump [FILE]
- Shows information about BIOS, system, mainboard and chassis from a binary dump file.
- free -h
- Shows free and used memory.
- hdparm -g /dev/[DEVICE]
- Shows drive geometry of the specified [DEVICE].
Execute with sudo / Caution when using - hdparm -i /dev/[DEVICE]
- Shows drive information about the specified [DEVICE].
Execute with sudo / Caution when using - hdparm -tT /dev/[DEVICE]
- Performs a read-speed test for the specified [DEVICE].
Execute with sudo / Caution when using - lsblk
- Shows information about block devices.
- lspci
- Shows information about PCI devices.
- lspci -tv
- Shows information about PCI devices as tree.
- lspci -v
- Shows verbose information about PCI devices.
- lsusb
- Shows information about USB devices.
- lsusb -tv
- Shows information about USB devices as tree.
- lsusb -v
- Shows verbose information about USB devices.
Navigation
- cd ..
- Goes to the parent directory.
- cd [DIRECTORY]
- Goes to the specified [DIRECTORY].
- cd ~
- Goes to the users hone directory.
Network
- dig [HOST] ANY
- Shows DNS information for a [HOST].
- ip addr
- Shows addresses assigned to all network interfaces.
- ip route
- Shows the routing table.
- ping [HOST]
- Performs a ping to a given [HOST].
- ss -ap
- Shows a list with all open sockets, including the ports and the processes using these sockets.
- traceroute -I [HOST]
- Traces the route to a [HOST] per ICMP ECHO.
- whois [HOST]
- Shows whois information for a [HOST].
Processes
- kill [PID]
- Kills a process with the specified [PID].
Caution when using - killall [NAME]
- Kills all processes with the specified [NAME].
- lsof
- Lists all files opened by running processes.
- pkill [NAME]
- Kills a process with the specified [NAME].
Caution when using - pmap [PID]
- Shows the memory map of the process specified by its [PID].
- ps -aux
- Shows all processes running on the system.
- pstree
- Shows running processes as tree.
- top
- Shows running processes in real-time.
Search
- find [PATH] -name [EXPRESSION]
- Searches in a given [PATH] for file names with the specified [TERM] (incl. placeholders like "*" and "?").
- grep -Hnir [TERM] [DIRECTORY]
- Searches recursive for a case-invariant [TERM] in all files of a [DIRECTORY] and display the filename and line number.
- grep -i [TERM] [FILE]
- Searches for a [TERM] in a [FILE].
- locate [TERM]
- Search for file names with a given [TERM].
- ls
- Lists files in the current directory.
- ls -la
- Lists all files in the current directory with additional information.
Shell Special Commands
- !!
- Executes the last command.
Caution when using - exit
- Exits the current shell.
System Information
- cal
- Shows a calendar for the current month. The parameter "-w" adds week numbers.
- date
- Shows the current date and time.
- date -R
- Shows the current date and time in the RFC-5322 format.
- date -u
- Shows the current date and time as Coordinated Universal Time (UTC).
- hostname
- Shows the hostname of the system.
- hostname -i
- Shows the IP address of the system.
- last reboot
- Shows a list with the last system reboots.
- uname -a
- Shows system and kernel information like operating system name and version, machine name and kernel release.
- uptime -p
- Shows how long the system has been running.
- uptime -s
- Shows the date and time since the system is running.
Users and Groups
- cat /etc/group
- Shows the file "/etc/group" with all group names and group IDs.
- cat /etc/passwd
- Shows the file "/etc/passwd" with all user names and user IDs.
- groupadd [GROUP]
- Creates a new group with the specified [GROUP] name.
Execute with sudo - groupdel [GROUP]
- Removes the group specified by [GROUP].
Execute with sudo / Caution when using - groups
- Shows the current group names.
- id
- Shows user and group information for the current user.
- id -un
- Shows the own user name. Same as "whoami".
- id [USER]
- Shows user and group information for the specified [USER].
- last
- Shows a list with the last logged in users.
- useradd [USER]
- Creates a new user with the specified [USER] name.
Execute with sudo - userdel [USER]
- Removes the user specified by [USER].
Execute with sudo / Caution when using - usermod -aG [GROUP] [USER]
- Adds a [USER] to the specified [GROUP]. Without option "-a" all other groups of the user will be replaced with the new group!
Execute with sudo / Caution when using - users
- Shows the currently logged in users.
- w
- Shows a list with the currently logged in users and their activity.
- who
- Shows a list with the currently logged in users.
- who -b
- Shows the date and time of the last system boot.
- whoami
- Shows the own user name. Same as "id -un".
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