Linux Command Line Cheat Sheet
Table of Contents
- System Information
- Hardware Information
- Performance Monitoring and Statistics
- User Information and Management
- File and Directory Commands
- Process Management
- File Permission
- Networking
- Archives
- Installing Packages
- Search
- SSH Logins
- FIle Transfer
- Disk Usage
- Directory Navigation
uname -a # Display Linux system information
uname -r # Display kernel release information
cat /etc/redhat-release # Show which version of redhat installed
uptime # Show how long the system has been running + load
hostname # Show system host name
hostname -I # Display the IP addresses of the host
last reboot # Show system reboot history
date # Show the current date and time
cal # Show this month's calendar
w # Display who is online
whoami # Who you are logged in as
2
Hardware Information
dmesg # Display messages in kernel ring buffer
cat /proc/cpuinfo # Display CPU information
cat /proc/meminfo # Display memory information
free -h # Display free and used memory ( -h for human readable,
-m for MB, -g for GB.)
lspci -tv # Display PCI devices
lsusb -tv # Display USB devices
dmidecode # Display DMI/SMBIOS (hardware info) from the BIOS
hdparm -i /dev/sda # Show info about disk sda
hdparm -tT /dev/sda # Perform a read speed test on disk sda
badblocks -s /dev/sda # Test for unreadable blocks on disk sda
3
Performance Monitoring and Statistics
top # Display and manage the top processes
htop # Interactive process viewer (top alternative)
mpstat 1 # Display processor related statistics
vmstat 1 # Display virtual memory statistics
iostat 1 # Display I/O statistics
tail 100 /var/log/messages # Display the last 100 syslog messages (Use
/var/log/syslog for Debian based systems.)
tcpdump -i eth0 # Capture and display all packets on interface eth0
tcpdump -i eth0 'port 80' # Monitor all traffic on port 80 ( HTTP )
lsof # List all open files on the system
lsof -u user # List files opened by user
free -h # Display free and used memory ( -h for human
readable, -m for MB, -g for GB.)
watch df -h # Execute "df -h", showing periodic updates
4
User Information and Management
id # Display the user and group ids of your
current user.
last # Display the last users who have logged onto
the system.
who # Show who is logged into the system.
w # Show who is logged in and what they are
doing.
groupadd test # Create a group named "test".
useradd -c "John Smith" -m john # Create an account named john, with a
comment of "John Smith" and create the user's
home directory.
userdel john # Delete the john account.
usermod -aG sales john # Add the john account to the sales group
5
File and Directory Commands
ls -al # List all files in a long listing (detailed) format
pwd # Display the present working directory
mkdir directory # Create a directory
rm file # Remove (delete) file
rm -r directory # Remove the directory and its contents
recursively
rm -f file # Force removal of file without prompting for
confirmation
rm -rf directory # Forcefully remove directory recursively
cp file1 file2 # Copy file1 to file2
cp -r source_dir dest # copy source to dest
mv file1 file2 # rename or move file
ln -s /path/to/file/ linkname touch file # crate symbolic link
cat file # view the contents the file
less file # browse through a text file
head file # Display the first 10 lines of a file
tail file # display the last 10 lines of a file
tail -f file # display the last 10 lines of file and "follow" the file as it grows.
6
Process Management
ps # Display your currently running processes
ps -ef # Display all the currently running processes on the
system.
ps -ef | grep processname # Display process information for processname
top # Display and manage the top processes
htop # Interactive process viewer (top alternative)
kill pid # Kill process with process ID of p id
killall processname # Kill all processes named processname
program & # Start program in the background
bg # Display stopped or background jobs
fg # Brings the most recent background job to
foreground
fg n # Brings job n to the foreground
7
File Permission
U G W
rwx rwx rwx chmod 777 filename
rwx rwx r-x chmod 775 filename
rwx r-x r-x chmod 755 filename
rw- rw- r-- chmod 664 filename
rw- r-- r-- chmod 644 filename
LEGEND
U = User
G = Group
W = World
r = read
w = write
x = execute
- = no access
8
Networking
ifconfig -a # Display all network interfaces and ip address
ifconfig eth0 # Display eth0 address and details
ethtool eth0 # Query or control network driver and hardware settings
ping host # Send ICMP echo request to host
whois domain # Display whois information for domain
dig domain # Display DNS information for domain
dig -x IP_ADDRESS # Reverse lookup of IP_ADDRESS
host domain # Display DNS ip address for domain
hostname -i # Display the network address of the host name.
hostname -I # Display all local ip addresses
wget http://domain.com/file # Download http://domain.com/file
netstat -nutlp # Display listening tcp and udp ports and corresponding programs
9
Archives
tar cf archive.tar directory # Create tar named archive.tar containing
directory .
tar xf archive.tar # Extract the contents from archive.tar .
tar czf archive.tar.gz directory # Create a gzip compressed tar file name
archive.tar.gz .
tar xzf archive.tar.gz # Extract a gzip compressed tar file.
tar cjf archive.tar.bz2 directory # Create a tar file with bzip2 compression
tar xjf archive.tar.bz2 # Extract a bzip2 compressed tar file.
10
Installing Packages
yum search keyword # Search for a package by keyword .
yum install package # Install package .
yum info package # Display description and summary information
about package .
rpm -i package.rpm # Install package from local file named
package.rpm
yum remove package # Remove/uninstall package .
tar zxvf sourcecode.tar.gz # install software from source code
cd sourcecode
./configure
make
make install
11
Search
grep pattern file # Search for pattern in file
grep -r pattern directory # Search recursively for pattern in directory
locate name # Find files and directories by name
find /home/john -name 'prefix*'
# Find files in /home/john that start with "prefix".
find /home -size +100M # Find files larger than 100MB in /home
12
SSH Logins
ssh host # Connect to host as your local username.
ssh user@host # Connect to host as user
ssh -p port user@host # Connect to host using port
13
File Transfer
scp file.txt server:/tmp # Secure copy file.txt to the /tmp folder on
server
scp server:/var/www/*.html /tmp # Copy *.html files from server to the local
/tmp folder.
scp -r server:/var/www /tmp # Copy all files and directories recursively from
server to the current system's /tmp folder.
rsync -a /home /backups/ # Synchronize /home to /backups/home
rsync -avz /home server:/backups/ # Synchronize files /directores between the local and remote
systems with compression enabled
14
Disk usage
df -h # Show free and used space on mounted filesystems
df -i # Show free and used inodes on mounted filesystems
fdisk -l # Display disks partitions sizes and types
du -ah # Display disk usage for all files and directories in
human readable format
du -sh # Display total disk usage off the current directory
15
Directory Navigation
cd .. # To go up one level of the directory tree. (Change into
the parent directory.)
cd # Go to the $HOME directory
cd /etc # Change to the /etc directory
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