3.1.a linux commands reference
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This document provides a summary of common Unix/Linux commands organized into categories including file commands, process management, file permissions, SSH, searching, system info, compression, network, installation, and shortcuts. It lists commands like ls, cd, mkdir, rm, cp, mv, tar, gzip, ping, whois, dig, and more along with brief descriptions and common arguments.
3.1.a linux commands reference
- 1. Unix/Linux Command Reference .com 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 exist mv file1 file2 – rename or move file1 to file2 if file2 is an existing directory, moves 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 Process Management ps – display your currently active processes top – display all running processes kill pid – kill process id pid killall proc – kill all processes named proc * bg – lists stopped or background jobs; resume a stopped job in the background fg – brings the most recent job to foreground fg n – brings job n to the foreground File Permissions chmod octal file – change the permissions of file to octal, which can be found separately for user, group, and world by adding: ● 4 – read (r) ● 2 – write (w) ● 1 – execute (x) Examples: chmod 777 – read, write, execute for all chmod 755 – rwx for owner, rx for group and world For more options, see man chmod. 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 your 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 – show the current date and time cal – show this month's calendar 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 locations 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 file.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 – compresses file and renames it to file.gz gzip -d file.gz – decompresses file.gz back to file Network ping host – ping host and output results 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 Installation Install from source: ./configure make make install 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, resume with fg in the foreground or bg in the background Ctrl+D – log out of current session, similar to exit Ctrl+W – erases one word in the current line Ctrl+U – erases the whole line Ctrl+R – type to bring up a recent command !! - repeats the last command exit – log out of current session * use with extreme caution.