Unix/Linux Commands
| File Commands | |
| ls | Displays directory listing |
|
ls -al |
Displays formatted listing with hidden files |
| cd | Change to home directory |
|
cd dir |
Change directory to dir |
| pwd | Show current directory |
| mkdir dir | Create a directory dir |
| rm file | Delete file |
|
rm -r dir |
Delete directory dir |
|
rm -f file |
Force remove file |
|
rm rf dir |
Force remove directory dir Note: Use with extreme caution |
| cp file1 file2 | Copy file1 to file2 |
|
cp -r dir1 dir2 |
Copy dir1 to dir2 Creates dir2 if it does not exist |
| mv file1 file2 | Rename or move file1 to file2 |
| ln -s file link | Create symbolic link link to file |
| touch file | Create or update file |
| cat > file | Places standard input into file |
| more file | Outputs the content of file |
| head file | Outputs the first 10 lines of file |
| tail file | Outputs the last 10 lines of file |
|
tail -f file |
Outputs the contents of file at is grows, starting with the last 10 lines |
| Process Management | |
| ps | Displays currently active processes |
| top | Display all running processes |
| kill pid | Kills process id pid |
| killall proc* | Kills all processes named proc Note: Use with extreme caution |
| bg | Lists stopped or background jobs Resume a stopped job in background |
| fg | Brings most recent job to foreground |
|
fg jobname |
Brings job jobname to foreground |
| File Permissions | |
| chmod octal file |
Change the permissions of file to octal , which can be found separately for user, group, and other by adding:
To form the octal add the values of r, w, or x. The first digit stands for the user, the second stands for the group, and the last digit stands for world. Ex: chmod 777 file - read, write, execute (rwx) for all Ex: chmod 755 file - rwx for user, rw for group and world |
| SSH | |
| ssh user@host | Connect to host as user |
|
ssh -p port user@host |
Connect to host on port port as user |
|
ssh -copy -id user@host |
Add you key to host for user to enable a keyed or passwordless login |
| Searching | |
| grep pattern files | Search for pattern in files |
| grep -r pattern dir | Search recursively for pattern in dir |
| command | grep pattern | Search for pattern in the output of command |
| locate file | Find all instances of file |
| System Info | |
| date | Shows the current date and time |
| cal | Shows this month's calendar |
| uptime | Shows current uptime |
| w | Displays who is online |
| whoami | Displays who you are logged in as |
| finger user | Displays information about user |
| uname -a | Shows kernel information |
| cat /proc/cpuinfo | cpu information |
| cat /proc/meminfo | memory information |
| man command | Shows the manual for the command |
| df | Shows disk usage |
| du | Shows directory space usage |
| free | Shows memory and swap usage |
| whereis app | Shows possible locations of app |
| which app | Shows which app will be run by default |
| Compression | |
| tar cf file.tar files | Creates a tar named file.tar containing files |
| tar xf file.tar | Extract the files from file.tar |
| tar czf file.tar.gz files | Creates a tar named file.tar.gz containing files with Gzip compression |
| tar xzf file.tar.gz | Extract the files from file.tar.gz or file.tgz with Gzip |
| tar cjf file.tar.bz2 files | Creates a tar named file.tar.gz containing files with Bzip2 compression |
| tar xjf file.tar.bz2 | Extract the files from file.tar.bz2 with Bzip2 |
| gzip file | Compresses file and renames it to file.gz |
| gzip -d file.gz | Decompresses file.gz back to file |
| Network | |
| ping host | Pings host and outputs results |
| whois domain | Gets whois information for domain |
| dig domain | Gets DNS information for domain |
|
dig -x host |
Reverse lookup host |
| wget file | Downloads file |
|
wget -c file |
Continue a stopped download |
| Installation | |
| ./configure make make install |
Install from source |
| dpkg -i pkg.deb | Install a package (Debian) |
| rpm -Uvh pkg.rpm | Install a package (RPM) |
| Shortcuts | |
| Ctrl + C | Halts the current command |
| Ctrl + Z | Stops the current command |
| Ctrl + D | Log out of current session; similar to exit |
| Ctrl + W | Erases one word in the current line |
| Ctrl + U | Deletes from current cursor position to beginning of line |
| Ctrl + R | Type to bring in recent command |
| !! | Repeats the last command |
| exit | Log out of current session |