When using the resources of the National Supercomputing Center, teachers often find themselves at a loss with the Linux command line. This article systematically organizes the commonly used Linux system commands to provide valuable references for teachers and students.
We typically categorize common Linux commands into several groups: file operations, process management, system information, network operations, permission management, compression and packaging, etc. Below, we will list some of the most commonly used commands and provide brief explanations.1. File and Directory Operations
ls # List directory contents
ls -l # Detailed list
ls -a # Show hidden files
ls -lh # Human-readable file sizes
cd # Change directory
cd ~ # Go to home directory
cd – # Return to the previous directory
cd .. # Parent directory
pwd # Display current directory path
mkdir # Create directory
mkdir -p # Create multi-level directories
rmdir # Remove empty directory
2. File Operations
cp # Copy file
cp -r # Recursively copy directory
mv # Move/rename file
rm # Remove file
rm -r # Recursively remove directory
rm -f # Force remove
touch # Create empty file/update timestamp
cat # Display file content
cat -n # Display line numbers
less # View file page by page
more # Basic version of paged viewing
head # Display file beginning
head -n 10 # Display first 10 lines
tail # Display file end
tail -f # Real-time track file changes
tail -n 20 # Display last 20 lines
3. File Searching and Finding
find /path -name “*.txt” # Find by name
find . -type f -size +1M # Find files larger than 1MB
find . -mtime -7 # Find files modified in the last 7 days
grep “pattern” file.txt # Search text in file
grep -r “hello” /path # Recursively search directory
grep -i “pattern” # Ignore case
grep -v “exclude” # Exclude matches
locate filename # Quickly find file (requires updatedb)
which command # Show command path
whereis command # Show command location
4. System Information Monitoring
top # Dynamically display processes (similar to Task Manager)
htop # Enhanced version of top (requires installation)
ps # Display process snapshot
ps aux # Display details of all processes
ps -ef # Complete format process list
free -h # Memory usage (human-readable)
df -h # Disk space usage (human-readable)
du -sh # Directory size statistics
uname -a # System kernel information
cat /etc/os-release # System version information
uptime # System uptime and load
who # Current logged-in users
w # Show who is logged in and what they are doing
5. Hardware Information
lscpu # CPU information
lsblk # Block device information
lspci # PCI device information
lsusb # USB device information
6. System Management
chmod # Change file permissions
chmod 755 file # Set permissions rwxr-xr-x
chmod +x script # Add execute permission
chown # Change file owner
chown user:group file
chgrp # Change file group
sudo # Execute command with superuser privileges
su # Switch user
7. Package Management
# Ubuntu/Debian
apt update && apt upgrade
apt install package
apt remove package
dpkg -i package.deb
# CentOS/RHEL/Fedora
yum install package # CentOS/RHEL
dnf install package # Fedora
rpm -ivh package.rpm
# Arch Linux
pacman -S package
8. Network Management
ping host # Test network connectivity
ping -c 4 google.com # Send 4 packets
ifconfig # Network interface configuration (older)
ip addr # Show IP address (recommended)
netstat # Network statistics
netstat -tuln # View listening ports
ss -tuln # Faster netstat alternative
traceroute host # Trace packet path
mtr host # Enhanced version of traceroute
wget url # Download file
wget -c url # Resume download
curl url # Transfer data
curl -O url # Download file
ssh user@host # SSH remote connection
scp file user@host:/path # Secure copy
9. Compression and Decompression
# Common tar combinations
tar -czf archive.tar.gz /path # Create gzip compression
tar -xzf archive.tar.gz # Decompress gzip
tar -cjf archive.tar.bz2 /path # Create bzip2 compression
tar -xjf archive.tar.bz2 # Decompress bzip2
# zip/unzip
zip archive.zip file1 file2
unzip archive.zip
# gzip/bzip2
gzip file # Compress file
gzip -d file.gz # Decompress file
bzip2 file # bzip2 compression
bunzip2 file.bz2 # bzip2 decompression
10. Text Management
wc file # Count lines, words, bytes
wc -l file # Count lines only
sort file # Sort file content
sort -r file # Reverse sort
sort -n file # Numeric sort
uniq file # Remove duplicate lines (requires sorting first)
uniq -c file # Count duplicates
cut -d: -f1 file # Extract fields by delimiter
cut -c1-5 file # Extract character range
awk ‘{print $1}’ file # Powerful text processing
sed ‘s/old/new/g’ file # Stream editor for text replacement
diff file1 file2 # Compare file differences
11. Other Useful Commands
history # Command history
!! # Execute the last command
!n # Execute the nth command in history
alias # Show aliases
alias ll=’ls -l’ # Create alias
echo “text” # Output text
echo $PATH # Output environment variable
date # Display current date and time
cal # Display calendar
man command # View command manual
whatis command # Brief command description
which command # Show command path
ln -s target link # Create symbolic link
12. Common Combination Techniques
# Piping and Redirection
command1 | command2 # Pipe transfer
ls > file.txt # Output redirection to file
ls >> file.txt # Append to file
grep “error” log.txt 2>&1 # Error output redirection
# Background Running
command & # Run in background
nohup command & # Continue running after terminal exit
# Command Combinations
(command1; command2) # Execute in sequence
command1 && command2 # Execute second only if first succeeds
command1 || command2 # Execute second only if first fails
# Find and Process
find . -name “*.log” -exec rm {} \; # Find and delete
grep -r “error” /var/log | wc -l # Count errors
13. Essential Knowledge for Beginners
Use the Tab key for auto-completion
Ctrl+C to interrupt the current command
Ctrl+D to exit terminal or end input
Ctrl+Z to pause process, fg to resume foreground, bg to resume background
clear to clear the screen
Use history | grep keyword to search command history
This list covers 90% of daily usage scenarios. It is recommended to master the basic commands first, and then delve into specific commands as needed.