Linux Common Command Manual

Summary: Organizing commonly used Linux commands, once organized, looks very comfortable and is easy to remember.

Shutdown/Reboot/Logout#

Common Command	Function
shutdown -h now	Shut down immediately
shutdown -h 10	Shut down in 10 minutes
shutdown -h 11:00	Shut down at 11:00
shutdown -h +10	Schedule shutdown (in 10 minutes)
shutdown -c	Cancel scheduled shutdown
shutdown -r now	Reboot
shutdown -r 10	Reboot in 10 minutes
shutdown -r 11:00	Scheduled reboot
reboot	Reboot
init 6	Reboot
init 0	Shut down immediately
telinit 0	Shut down
poweroff	Shut down immediately
halt	Shut down
sync	Synchronize buffer data to disk
logout	Logout from Shell

System Information and Performance Monitoring#

Common Command	Function
uname -a	View kernel/OS/CPU information
uname -r	View kernel version
uname -m	View processor architecture
arch	View processor architecture
hostname	View computer name
who	Display currently logged-in users
who am i	Display username at login
whoami	Display current username
cat /proc/version	View Linux version information
cat /proc/cpuinfo	View CPU information
cat /proc/interrupts	View interrupts
cat /proc/loadavg	View system load
uptime	View system uptime, user count, load
env	View system environment variables
lsusb -tv	View system USB device information
lspci -tv	View system PCI device information
lsmod	View loaded system modules
grep MemTotal /proc/meminfo	View total memory
grep MemFree /proc/meminfo	View free memory
free -m	View memory usage and swap usage
date	Display system date and time
cal 2021	Display 2021 calendar
top	Dynamically display CPU/memory/process status
vmstat 1 20	Sample system status every 1 second, 20 times
iostat	View IO read/write/CPU usage
sar -d 1 10	Query disk performance

Disk and Partition#

Common Command	Function
fdisk -l	View all disk partitions
swapon -s	View all swap partitions
df -h	View disk usage and mount points
df -hl	Same as above
du -sh /dir	View the size of a specific directory
du -sk *	sort -rn
mount /dev/hda2 /mnt/hda2	Mount hda2 disk
mount -t ntfs /dev/sdc1 /mnt/usbhd1	Mount with specified filesystem type (e.g., ntfs)
mount -o loop xxx.iso /mnt/cdrom	Mount ISO file
umount -v /dev/sda1	Unmount by device name
umount -v /mnt/mymnt	Unmount by mount point
fuser -km /mnt/hda1	Force unmount (use with caution)

User and User Group#

Common Command	Function
useradd legalgeek	Create user
userdel -r legalgeek	Delete user
usermod -g group_name user_name	Modify user's group
usermod -aG group_name user_name	Add user to group
usermod -s /bin/ksh -d /home/codepig –g dev legalgeek	Modify legalgeek's login shell, home directory, and group
groups test	View groups of test user
groupadd group_name	Create user group
groupdel group_name	Delete user group
groupmod -n new_name old_name	Rename user group
su - user_name	Switch to user_name user
passwd	Change password
passwd legalgeek	Change password for a specific user
w	View active users
id legalgeek	View information for specified user legalgeek
last	View user login logs
crontab -l	View current user's scheduled tasks
cut -d: -f1 /etc/passwd	View all system users
cut -d: -f1 /etc/group	View all system groups

Network and Process Management#

Common Command	Function
ifconfig	View network interface properties
ifconfig eth0	View configuration of a specific network card
route -n	View routing table
netstat -lntp	View all listening ports
netstat -antp	View established TCP connections
netstat -lutp	View TCP/UDP status information
ifup eth0	Enable eth0 network device
ifdown eth0	Disable eth0 network device
iptables -L	View iptables rules
ifconfig eth0 192.168.1.1 netmask 255.255.255.0	Configure IP address
dhclient eth0	Enable eth0 in DHCP mode
route add -net 0/0 gw Gateway_IP	Configure default gateway
route add -net 192.168.0.0 netmask 255.255.0.0 gw 192.168.1.1	Configure static route to reach network '192.168.0.0/16'
route del 0/0 gw Gateway_IP	Delete static route
hostname	View hostname
host www.baidu.com	Resolve hostname
nslookup www.baidu.com	Query DNS records, check domain resolution status
ps -ef	View all processes
ps -ef	grep legalgeek
kill -s name	Kill process with specified name
kill -s pid	Kill process with specified pid
top	Display process status in real-time
vmstat 1 20	Sample system status every 1 second, 20 times
iostat	iostat
sar -u 1 10	Query CPU usage (once every second, 10 times)
sar -d 1 10	Query disk performance

Common System Service Commands#

Common Command	Function
chkconfig --list	List system services
service <service_name> status	View a specific service
service <service_name> start	Start a specific service
service <service_name> stop	Stop a specific service
service <service_name> restart	Restart a specific service
systemctl status <service_name>	View a specific service
systemctl start <service_name>	Start a specific service
systemctl stop <service_name>	Stop a specific service
systemctl restart <service_name>	Restart a specific service
systemctl enable <service_name>	Disable auto-start
systemctl disable <service_name>	Disable auto-start

File and Directory Operations#

Common Command	Function
cd <directory_name>	Enter a specific directory
cd ..	Go to the parent directory
cd ../..	Go back two levels in the directory
cd	Enter the home directory
cd -	Go back to the previous directory
pwd	Display current path
ls	View file directory list
ls -F	View contents of the directory (show whether it's a file or directory)
ls -l	View detailed list of files and directories
ls -a	View hidden files
ls -lh	View detailed list of files and directories (enhanced readability of file sizes)
ls -lSr	View file and directory list (sorted by file size in ascending order)
tree	View tree structure of files and directories
mkdir <directory_name>	Create directory
mkdir dir1 dir2	Create two directories at once
mkdir -p /tmp/dir1/dir2	Create directory tree
rm -f file1	Delete 'file1' file
rmdir dir1	Delete 'dir1' directory
rm -rf dir1	Delete 'dir1' directory and its contents
rm -rf dir1 dir2	Delete two directories and their contents at once
mv old_dir new_dir	Rename/move directory
cp file1 file2	Copy file
cp dir/* .	Copy all files from a directory to the current directory
cp -a dir1 dir2	Copy directory
cp -a /tmp/dir1 .	Copy a directory to the current directory
ln -s file1 link1	Create a symbolic link to a file/directory
ln file1 lnk1	Create a hard link to a file/directory
find / -name file1	Search for file/directory starting from the root directory
find / -user user1	Search for files/directories owned by user1
find /dir -name *.bin	Search for files with .bin suffix in directory /dir
locate	Quickly locate files
locate *.mp4	Find files ending with .mp4
whereis	Show the path of a binary/executable file
which	Find a binary file in system directories
chmod ugo+rwx dir1	Set read (r), write (w), and execute (x) permissions for owner (u), group (g), and others (o) on directory
chmod go-rwx dir1	Remove read, write, and execute permissions for group (g) and others (o) on directory
chown user1 file1	Change file owner
chown -R user1 dir1	Change directory owner
chgrp group1 file1	Change file group
chown user1 file1	Change file owner and group

File Viewing and Processing#

Common Command	Function
cat file1	View file content
cat -n file1	View content and show line numbers
tac file1	View file content starting from the last line
more file1	more file1
less file1	Similar to more command, but allows reverse operation
head -2 file1	View the first two lines of the file
tail -2 file1	View the last two lines of the file
tail -f /log/msg	Real-time view of content added to the file
grep legalgeek hello.txt	Search for the keyword legalgeek in hello.txt
grep ^sheep hello.txt	Search for content starting with sheep in hello.txt
grep [0-9] hello.txt	Select all lines in hello.txt containing numbers
sed 's/s1/s2/g' hello.txt	Replace s1 with s2 in hello.txt
sed '/^$/d' hello.txt	Delete all empty lines from hello.txt
sed '/ *#/d; /^$/d' hello.txt	Delete all comments and empty lines from hello.txt
sed -e '1d' hello.txt	Exclude the first line from hello.txt
sed -n '/s1/p' hello.txt	View lines containing the keyword "s1"
sed -e 's/ *$//' hello.txt	Remove trailing whitespace from each line
sed -e 's/s1//g' hello.txt	Remove only the word s1 from the document and keep the rest
sed -n '1,5p;5q' hello.txt	View content from the first line to the 5th line
sed -n '5p;5q' hello.txt	View the 5th line
paste file1 file2	Merge content of two files or columns
paste -d '+' file1 file2	Merge content of two files or columns, separated by "+"
sort file1 file2	Sort content of two files
comm -1 file1 file2	Compare content of two files (remove content in 'file1')
comm -2 file1 file2	Compare content of two files (remove content in 'file2')
comm -3 file1 file2	Compare content of two files (remove common parts)

Packaging and Unpacking#

Common Command	Function
zip xxx.zip file	Compress to zip package
zip -r xxx.zip file1 file2 dir1	Compress multiple files and directories into zip package
unzip xxx.zip	Unzip zip package
tar -cvf xxx.tar file	Create uncompressed tar package
tar -cvf xxx.tar file1 file2 dir1	Create tar package from multiple files and directories
tar -tf xxx.tar	View contents of tar package
tar -xvf xxx.tar	Unzip tar package
tar -xvf xxx.tar -C /dir	Unzip tar package to specified directory
tar -cvfj xxx.tar.bz2 dir	Create bz2 compressed package
tar -jxvf xxx.tar.bz2	Unzip bz2 compressed package
tar -cvfz xxx.tar.gz dir	Create gzip compressed package
tar -zxvf xxx.tar.gz	Unzip gzip compressed package
bunzip2 xxx.bz2	Unzip bz2 compressed package
bzip2 filename	Compress file
gunzip xxx.gz	Unzip gzip compressed package
gzip filename	Compress file
gzip -9 filename	Maximum compression

RPM Package Management Commands#

Common Command	Function
rpm -qa	View installed rpm packages
rpm -q pkg_name	Query a specific rpm package
rpm -q --whatprovides xxx	Show which package provides xxx functionality
rpm -q --whatrequires xxx	Show which package depends on xxx functionality
rpm -q --changelog xxx	Show changelog of xxx package
rpm -qi pkg_name	View detailed information of a package
rpm -qd pkg_name	Query documentation provided by a package
rpm -qc pkg_name	View configuration files provided by installed rpm package
rpm -ql pkg_name	View files installed by a package
rpm -qf filename	View which package a file belongs to
rpm -qR pkg_name	Query package dependencies
rpm -ivh xxx.rpm	Install rpm package
rpm -ivh --test xxx.rpm	Test install rpm package
rpm -ivh --nodeps xxx.rpm	Install rpm package ignoring dependencies
rpm -e xxx	Uninstall package
rpm -Fvh pkg_name	Upgrade an already installed rpm package
rpm -Uvh pkg_name	Upgrade rpm package (install if not installed)
rpm -V pkg_name	Verify detailed information of RPM package

YUM Package Management Commands#

Common Command	Function
yum repolist enabled	Show available source repositories
yum search pkg_name	Search for software package
yum install pkg_name	Download and install software package
yum install --downloadonly pkg_name	Download without installing
yum list	Show all packages
yum list installed	View currently installed packages
yum list updates	View updatable package list
yum check-update	View upgradable software packages
yum update	Update all software packages
yum update pkg_name	Upgrade specified software package
yum deplist pkg_name	List package dependencies
yum remove pkg_name	Remove software package
yum clean all	Clear cache
yum clean packages	Clear cached packages
yum clean headers	Clear cached headers

DPKG Package Management Commands#

Common Command	Function
dpkg -c xxx.deb	List contents of deb package
dpkg -i xxx.deb	Install/upgrade deb package
dpkg -r pkg_name	Remove deb package
dpkg -P pkg_name	Remove deb package (without configuration)
dpkg -l	View installed deb packages
dpkg -l pkg_name	Show general information of package
dpkg -L pkg_name	View files installed by deb package
dpkg -s pkg_name	View detailed information of package
dpkg –unpack xxx.deb	Unpack contents of deb package

APT Software Tools#

Common Command	Function
apt-cache search pkg_name	Search for software package
apt-cache show pkg_name	Get overview information of package
apt-get install pkg_name	Install/upgrade software package
apt-get purge pkg_name	Uninstall software (including configuration)
apt-get remove pkg_name	Uninstall software (excluding configuration)
apt-get update	Update package index information
apt-get upgrade	Update installed software packages
apt-get clean	Clean cache