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
