Basic UNIX commands :-
• To change the current directory to another directory
Syntax- cd
[path_of_directory]
Note: - UNIX is case sensitive so type the same directory name
[localhost@root ~]$ cd /home/user/data
[localhost@root data]$
• To change the current directory to your home directory
Syntax- cd
[localhost@root data]$ cd
[localhost@root ~]$
Note: - The current directory should now be your home directory.
• To create a directory inside the current directory
Syntax- mkdir [name_of_new_directory]
[localhost@root ~]$ mkdir test
Test directory now should exist within
the current directory.
• The cp command is use to make a copy of a file
Syntax- cp
[name of file] [name of copy]
[localhost@root ~]$ cp old_directory new_directory_name
• mv command is used
to either rename an existing file or folder to something different
or to “move” a file from one directory
to another.
Syntax- mv [name of existing file] [new name
for existing file]
[localhost@root ~]$ mv name_of_existing_file
new_name_for_existing_file
• To move an existing file, type
Syntax- mv [name of existing file] [path of
new location]
[localhost@root inteljasper]$ mv
file_name path_where_to_copy
[localhost@root
~]$ mv mydir /home/localhost/test/
• rm command is used to delete a file, to remove an existing file,
type
Syntax- rm [name of file]
[localhost@root ~]$ rm file_name
• rmdir command is a separate command for removing directories. To
remove a directory, the directory must be empty. To remove an existing
directory, type
Syntax- rmdir [name of directory]
[localhost@root ~]$ rmdir
directory_name
Some basic useful commands and there output: -
• date
Syntax- [localhost@root~]$date
Output
- Fri Dec 23 10:30:05 IST 2011
• tput clear - To clear the screen clear is an argument of tput
command.
Syntax- [localhost@root~]$ tput clear
• cal – Calendar of current month
Syntax- [localhost@root~]$ cal
• cal 1 1987 – to see the calendar of January 1987
Syntax- [localhost@root~]$ cal 1 1987
• who – to see who are the users? It will show all the users who
are currently logged in.
Syntax- [localhost@root~]$ who
Output- localhost pts/1 2011-12-23 10:29 (sharad-pc.home)
• ps – to view the running process
Syntax- [localhost@root~]$ps
Output- PID TTY TIME CMD
14493
pts/1 00:00:00
bash
14691
pts/1 00:00:00
ps
• ksh -
Syntax- [localhost@root~]$ksh Korn shell it will show only like this
Output
- $
Syntax- $ sh Bourne
shell(sh-3.2$)
Syntax- $
csh C
shell
Syntax- $bash Bash shell(original shell)
Output- [localhost@root~]$
• ls – to list all the files
Syntax- [localhost@root~]$ls
files
are arranged alphabetically with uppercase having precedence over lower case)
• ls
chap*
Syntax- [localhost@root~]$ls chap*
It will list all files starting with
chap word
• ls –l chap*
Syntax- [localhost@root~]$ls -l chap*
Output- -rw-rw-r-- 1 localhost localhost 286 Dec 19 12:20 list
• ls > list
Syntax- [localhost@root~]$ls > list
Directing
output to a file name list. Prompts return no display on the terminal
(">" is a
metacharacters )
• cat list - to open any file
Syntax- [localhost@root~]$cat
list
list
is a file name where all the list of files are stored you can give any name.
• wc list -
Syntax- [localhost@root~]$wc list Counting number of lines in a file
Output- 6 6 42 list means 6 lines,6words,42 character
• ls | wc - Feeding output of one command to
another using "|"pipeline
Syntax- [localhost@root~]$ls | wc or
[localhost@root~]$ls|wc
• Programing with the shell
You can assign a value to a variable
at the prompt
Syntax- [localhost@root~]$ x=5
No space on either side of = and then
evaluate the value of this variable with the echo command
Syntax- [localhost@root~]$ echo $x
Output- op/ 5
• Exit : signing off
Syntax- [localhost@root~]$exit
Or [localhost@root~]$logout
• Syntax- [localhost@root~]$echo sharad gupta
Output- o/p sharad gupta
•
Syntax- [localhost@root~]$echo $PATH
•
Syntax- [localhost@root~]$type ls
Output- ls is aliased to `ls --color=tty'
•
Syntax- [localhost@root~]$type echo to know which command it is
Output- echo is a shell builtin
• Combined
commands
Syntax- [localhost@root~]$wc list; ls -l list
Output- 18 18 289 list
-rw-rw-r-- 1 localhost localhost 289
Dec 19 12:26 list
• Save the
results in new file
Syntax- [localhost@root~]$ ( wc test ;
ls -l test ) > newlist
• To know
about any command
Syntax- [localhost@root~]$man -k awk
Output- English (3pm) - use nice English (or awk) names for
ugly
punctuation variables
a2p (1) - Awk to Perl translator
awk (1p) - pattern scanning and processing
language
gawk (1) - pattern scanning and processing
language
gawk (rpm) - The GNU version of the awk
text processing utility.
