Linux/SSH Command Line Quick Reference

File and Directory Management

• ls – List contents of current directory

• ls -a – List all files including hidden

• ls -la – List all with details (permissions, size, timestamp)

• cp source dest – Copy file

• cp -R dir1 dir2 – Copy directory recursively

• mv oldname newname – Move or rename file or directory

• mkdir dirname – Create directory

• rmdir dirname – Delete empty directory

• rm filename – Delete file

• rm -rf dirname – Delete directory recursively

Navigating the Filesystem

• cd /path – Change to directory

• cd .. – Move to parent directory

• cd ~ – Move to home directory

• cd - – Switch to previous directory

• pwd – Show current directory

File Editing

• nano filename – Edit file using nano

• pico filename – Edit file using pico (older systems)

Archive and Compression

• tar -zcf archive.tar.gz file_or_dir – Create compressed tarball

• tar -zxpf file.tar.gz – Extract .tar.gz

• tar -xpf file.tar – Extract .tar

• gunzip file.gz – Uncompress .gz

File Search

• find / -user username – Find files owned by user

• whereis command – Locate binary/source/man page

• updatedb – Update file locate database

• locate filename – Fast file lookup

System Information

• df -c – Disk usage

• quota – Show disk quota

• uptime – Show system uptime

• uname -a – Show OS info

• whoami – Show current user

• who – List logged-in users

• last – Show last logins

• ps – Show running processes

• ps -x – Show current user processes

• ps aux – Show all processes

• top – Live process monitor (press q to quit)

• sar -q – System load averages every 10 mins

• netstat -np – Show active connections

Process Management

• kill PID – Kill process by PID

• kill -9 PID – Force kill process

• killall name – Kill all processes by name or user

Networking

• ftp server.com – Connect to FTP

• lynx url – View webpage in terminal

Package and Service Management (RedHat-based)

• service servicename start|stop|restart|status – CentOS 6

• systemctl start|stop|restart|status servicename – CentOS 7+

Common services:

• httpd, mysql, named, exim, cpanel, proftpd, crond, chkservd, bandmin

Cron Jobs

• crontab -e – Edit root/user’s cron jobs

• crontab -u username -e – Edit another user’s cron jobs

Mail

• mail – Check local mail

WHM/cPanel Scripts (run as root)

• /scripts/pkgacct2 username – Manual backup

• /scripts/restorepkg username – Restore backup

• /scripts/killacct username – Terminate account

• /scripts/suspendacct username – Suspend account

• /scripts/unsuspendacct username – Unsuspend account

• /scripts/editquota username – Edit disk quota

• /scripts/fixinterchange – Fix Interchange issues

• /scripts/fixwebalizer – Fix stats

• /scripts/restartsrv servicename – Restart service

• /scripts/mailperm – Fix mail permissions

• /scripts/mysqlpasswd – Change MySQL password

• /scripts/findtrojans – Scan for trojans

• /scripts/fixtrojans – Remove trojans

File Viewing & Logs

• tail -n filename – View last n lines of file

Miscellaneous

• --help – View help for most commands (e.g., tar --help)

• reboot – Reboot server

• mv – Also used to rename directories

Maintenance

• Delete MRTG:

  rpm -e --nodeps \ $(rpm -q | grep mrtg)

• Clear /tmp folder:

rm -Rf /tmp/c*
rm -Rf /tmp/s*
rm -Rf /tmp/p*
rm -Rf /tmp/*_*
rm -Rf /tmp/*-*