Following are the useful linux commands:
FILE COMMANDS
- ls – directory listing
- ls -al - formatted listing with hidden files
- cd dir – change directory to dir
- cd – change to home
- 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 *
- cp file1 file2 – copy file1 to file2
- cp -r dir1 dir2 – copy dir1 to dir2; create dir2 if it doesn’t exit
- mv file1 file2 - rename or move file1 to file2 if file2 is an existing directory, move file1 into directory 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 – output the contents of file
- head file – output the first 10 lines of file
- tail file – output the last 10 lines of file
- tail -f file – output the contents of file as it grows, starting with the last 10 lines
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
PROCESS MANAGEMENT
- ps – display your currently active proceess
- top – display all running process
- kill pid – kill process id pid
- killall proc – kill all process named proc (use with extreme caution)
- bg – lists stopped or backgrpund jobs; resume a stopped job in the backgrpund
- fg – brings the most recent job to foreground
- fg n – brings job n to the foreground
SYSTEM INFO
- date - show the current date and time
- cal – show this month’s calender
- uptime – show current uptime
- w – display who is online
- whoami – who you are logged in as
- finger user – display information about user
- uname -a – show kernel information
- cat /proc/cpuinfo – cpu information
- cat /proc/meminfo – memory information
- man command – show the manual for command
- df - show disk usage
- du – show directory space usage
- free – show memory and swap usage
- whereis app – show possible location of app
- which app – show which app will be run by default
COMPRESSION
- tar cf file.tar files - create a tar named file.tar containing files
- tar xf files.tar – extract the files from file.tar
- tar czf file.tar.gz files – create a tar with Gzip compression
- tar xzf file.tar.gz – extract a tar using Gzip
- tar cjf file.tar.bz2 – create a tar with Bzip2 compression
- tar xjf file.tar.bz2 – extract a tar using Bzip2
- gzip file – compress file and renamed it to file.gz
- gzip -d file.gz – decompress file.gz back to file
NETWORK
- ping host – ping host and output result
- whois domain – get whois information for domain
- dig domain – get DNS information for domain
- dig -x host – reverse lookup host
- wget file – download file
- wget -c file – continue a stopped download
