Thursday 30 October 2014

Unix/Linux Command Reference

Unix/Linux Command Reference
File Commands
1. ls                         Directory listing
2. ls –al                   Formatted listing with hidden files
3. ls -lt                    Sorting the Formatted listing by time modification
4. cd dir                  Change directory to dir
5. cd                       Change to home directory
6. pwd                    Show current working directory
7. mkdir dir            Creating a directory dir
8. cat >file         Places the standard input into the file
9. more file             Output the contents of the file
10. head file           Output the first 10 lines of the file
11. tail file              Output the last 10 lines of the file
12. tail -f file         Output the contents of file as it grows, starting with the last 10 lines
13. touch file         Create or update file
14. rm file              Deleting the file
15. rm -r dir           Deleting the directory
16. rm -f file           Force to remove the file
17. rm -rf dir           Force to remove the directory dir
18. cp file1 file2     Copy the contents of file1 to file2
19. cp -r dir1 dir2   Copy dir1 to dir2;create dir2 if not present
20. mv file1 file2    Rename or move file1 to file2,if file2 is an existing directory
21. ln -s file            link Create symbolic link link to file

Process management
1. ps                      To display the currently working processes
2. top                     Display all running process Unix/Linux Command Reference
3. kill pid               Kill the process with given pid
4. killall proc         Kill all the process named proc
5. pkill pattern       Will kill all processes matching the pattern
6. bg                      List stopped or background jobs,resume a stopped job in the  background 
7. fg                       Brings the most recent job to foreground
8. fg n                    Brings job n to the foreground


File permission
1. chmod octal file Change the permission of file to octal,which can be found separately for user,group,world by adding,
• 4-read(r)
• 2-write(w)
• 1-execute(x)


Searching
1. grep                        pattern file Search for pattern in file
2. grep -r                    pattern dir Search recursively for pattern in dir
3. command | grep :   pattern  Search pattern in the output of a command
4. locate file               Find all instances of file
5. find . -name           filename Searches in the current directory (represented by
a period) and below it, for files and directories with names starting with filename 
6. pgrep:                    pattern Searches for all the named processes , that matches with the pattern and, by default, returns their ID



System Info
1. date             Show the current date and time
2. cal               Show this month's calender
3. uptime         Show current uptime
4. w                 Display who is on line
5. whoami       Who you are logged in as Unix/Linux Command Reference 6. finger user                             Display information about user
7. uname -a                   Show kernel information
8. cat /proc/cpuinfo       Cpu information
9. cat proc/meminfo     Memory information 
10. man                        command Show the manual for command
11. df                            Show the disk usage
12. du                           Show directory space usage
13. free                         Show memory and swap usage
14. whereis app            Show possible locations of app
15. which app               Show which applications will be run by default

Compression

1. tar cf file.tar file                    Create tar named file.tar containing file
2. tar xf file.tar                          Extract the files from file.tar
3. tar czf file.tar.gz files            Create a tar with Gzip compression
4. tar xzf file.tar.gz                    Extract a tar using Gzip
5. tar cjf file.tar.bz2                   Create tar with Bzip2 compression
6. tar xjf file.tar.bz2                   Extract a tar using Bzip2
7. gzip file                                  Compresses file and renames it to file.gz
8. gzip -d file.gz                         Decompresses file.gz back to file



Unix/Linux Command Reference Shortcuts
1. ctrl+c                   Halts the current command
2. ctrl+z                   Stops the current command, resume with fg in the foreground or bg in                                  the background
3. ctrl+d                   Logout the current session, similar to exit 
4. ctrl+w                  Erases one word in the current line
5. ctrl+u                   Erases the whole line
6. ctrl+r                   Type to bring up a recent command
7. !!                         Repeats the last command

8. exit                      Logout the current session

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