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Unix CLI Commands CheatSheet

Basic Commands

Show current directory
```
pwd
```

List files in a directory

ls
ls -l  # long format
ls -a  # include hidden files

Change directory
```
cd <directory>
```
Create a new directory
```
mkdir <directory>
```
Remove a directory
```
rmdir <directory>
```
Create an empty file or update the access and modification times of a file
```
touch <filename>
```

Remove a file

rm <filename>
rm -r <directory>  # remove directory and its contents

Viewing and Editing Files

Display the contents of a file
```
cat <filename>
```
Display the first few lines of a file
```
head <filename>
```
Display the last few lines of a file
```
tail <filename>
```
Open a file for editing in nano
```
nano <filename>
```
Open a file for editing in vim
```
vim <filename>
```

File and Directory Operations

Copy files and directories

cp <source> <destination>
cp -r <source> <destination>  # copy directories recursively

Move/rename files and directories
```
mv <source> <destination>
```

Permissions and Ownership

Change file permissions

chmod <permissions> <filename>
chmod 755 <filename>  # common permission set

Change file owner and group
```
chown <owner>:<group> <filename>
```
View file permissions
```
ls -l <filename>
```

System Information

Show current date and time
```
date
```
Show system uptime
```
uptime
```
Show who is logged in
```
who
```
Show current user
```
whoami
```
Display disk usage of a directory
```
du -sh <directory>
```
Display free and used memory
```
free -h
```
Show system information
```
uname -a
```

Networking

Display network interfaces and IP addresses
```
ifconfig
```
Check connectivity to a host
```
ping <hostname>
```
Display routing table
```
route -n
```
Display open network connections
```
netstat
```

Process Management

List running processes
```
ps aux
```
Display process tree
```
pstree
```
Terminate a process by PID
```
kill <pid>
```
Terminate a process by name
```
killall <process-name>
```
Show process usage and system load
```
top
```

Searching and Filtering

Search for a pattern in files
```
grep <pattern> <file>
```
Find files and directories
```
find <directory> -name <pattern>
```
Search for commands in the command history
```
history | grep <pattern>
```
Display command history
```
history
```

Archiving and Compression

Create a tar archive
```
tar -cvf <archive.tar> <files>
```
Extract a tar archive
```
tar -xvf <archive.tar>
```
Create a compressed archive (gzip)
```
tar -czvf <archive.tar.gz> <files>
```
Extract a compressed archive (gzip)
```
tar -xzvf <archive.tar.gz>
```
Compress a file with gzip
```
gzip <file>
```
Decompress a file with gzip
```
gunzip <file.gz>
```
Compress a file with bzip2
```
bzip2 <file>
```
Decompress a file with bzip2
```
bunzip2 <file.bz2>
```

Disk Usage and Management

Check disk space usage
```
df -h
```
Check inode usage
```
df -i
```
Check space usage of files and directories
```
du -sh <directory>
```

Environment Variables

Set an environment variable
```
export VAR_NAME=value
```
Show environment variables
```
printenv
```
Unset an environment variable
```
unset VAR_NAME
```

Miscellaneous

Echo text to the terminal
```
echo "Hello, World!"
```
Redirect output to a file
```
command > <file>
```
Append output to a file
```
command >> <file>
```

Chain multiple commands

command1 && command2
command1 || command2