SAP Administration Related UNIX Commands

Below  Unix Commands is used for SAP Administration

1.WHO

It displayes the all users in the system

2.WHO AM I

It displayes the information about the current user

format: username         terminal number          date and time

example: naresh           tty3a                    jun 10 09:15

3.TOUCH

It creates the new file with empty space . We can create more number of files at a time.

example: touch file1 file2 file3

4.CAT

It creates the new file with entered data.after entering the data press CTRL+D to end the file.

example: cat > file1

we can use CAT command to display the file contents

example: cat file1

5.cat file1 file2 > newfile

this command creates "newfile" and insert the two files data one after other (file1 and file2)

If the "newfile" already exists then it overwritten with new files data

6.cat file1 file2 >> newfile

If the "newfile" already having some data then we use this command to append the data to the precious data.

7.cp letter.a letter.b letters

This command copies letter.a and letter.b to the directory letters

8.cp /usr/aa16/chapter1  /usr/aa16/newbook/chap1

This command copies the chapter1 file to newbook directory

9.rm -i file

It removes the "file" with interactively, It asks for  confirmation before deleting the file.

10.mv test sample

This command renames the file test to sample

We can use this command to rename the directories also

11.ls

By using this command we can display the files

12 ls -a

By using this command we can display the files even hidden files also displayed

TO CREATE HIDDEN FILES :

Create the file starting with "."

example : cat > .filename

13. ls p*

It displayes the files whose name starts with "p"

example : pain

            parse

            pocket

14. ls ?ain

It displayes the files whose name starts with any letter and followed by "ain"

example : pain

            main

            rain

15. ls /mydir/*x

It display the files in the directory "mydir" if the last letter is "x"

16. ls [aeiou]*

It display the files whose name starts with a,e,i,o,u

17 ls [!aeiou]*

It display the files whose name starts with other than a,e,i,o,u

18. ls [a-m][b-d]??

It display the files whose name is starts with "a to m" and the second character is in the range of " b to d" and third and fourth are valid characters.

example : bcff

            eckp

19. ls -l

It displays the files with complete details

20. ln filename filename2

This command creates another link for the file "filename"

21. chmod

By using this command we can chane the permissions

We have three permissions

read

write

execute

Notation ally these are denoted with

r is for read

w is for write

x is for execute

Numerically these are denoted with

4 is for read

2 is for write

1 is for execute

example

Chmod  700 file1

          It gives the permissions as

          Rwx for user

          None for group

          None for others

Another form of chmod command is

Chmod [who] [+/-/=] [permissions] filename

Here

          Who means user or group or other

          Owner is denoted with u

          Group is denoted with g

          Others is denoted with o

          If none is specified all are assumed.

          +  is to add

-   is to remove

=  is to truncate and assigns the new permissions

Example

Chmod +w file1

It gives the write permissions to all

Chmod go-x file1

It removes the executable permissions form group and other.

Chmod go+r,go-w file1

It gives the read permissions to group and others, and removes the write permissions from group and others

Chmod 744 file1

It gives the permissions like rwxr—r--  to file1

22. umask

When u create any file some permissions are automatically assigned

How these permissions are assigned?

The default system wide permissions for unix are : 666

Subtract these permissions frome umask permissions then we will get the required permissions.

Example

Umask

By using this command we can retrive the umask(user file creation mask) permissions

For example these are 0022

First 0 indicates that what follows is an octal number

Second 0 indicates there is no permissions denied from owner

First 2 indicates that denied the write permissions from group

Second 2 indicates that denied the write permissions from others

For file the default permissions are

666-022=644(rw for users, write for group, write for others)

For directory the default permissions are

777-022=755(rwx for users, rx for group, rx for others)

To change the umask value :

Command: Umask value

Example

Command: Umask 242

Default permissions are :

For file the default permissions are

666-242=424(read for users, write for group, read for others)

For directory the default permissions are

777-242=535(rx for users, wx for group, rx for others)

23. rm

Command : rm –f letter

This command removes the file “letter” forcely . that is even if the file is write protected

24. ls –r :

Command : ls –r

this command displayes all the files in the current directory ,including the files present in the subdirectories

25. ls –s :

Command : ls –s

This command displays the files with size ( in blocks)

26. ls –i :

Command : ls –i

This command displays the files with inode number

27. lc :

Command : lc

This command displays the files in column wise

28. lf :

Command : lf

This command displays the files

                                      Ends with * for executable files

                                      Ends with  / for sub-directories

29. pwd :

Command : pwd

This command displayes the present working directory.

30. mkdir :

Command : mkdir dirname

It creates the directory “dirname”

Command : mkdir –p pathname

It creates the complete path as one by one directory

Example :

Command : mkdir –p home/datastage/naresh

This command first creates the directory “ home” then it creates “datastage” then it creates “naresh”.

31. rmdir :

Command : rmdir dirname

It removes the directory “dirname”

Command : rmdir –p path

It removes all the directories from right to left

32. cd

Command : cd dirname

This command would take you in “dirname”

Command : cd

This command would take you in to the “home directory”

33. bc :

command : bc

this command is for calculator purpose

34. factor :

Command : factor

It returns the “prime factors” of the given number

35. logname :

Command : logname

This command prints the “login name” of the user

36. id :

Command : id

This command prints the userid(uid) and  groupid(gid) of the current user.

37. uname :

Command : uname

It displayes the name of the unix system

Command : uname –x

It displayes the information like

                                     

                                     Release number

                                      Version number

                                      OEM number

                                      Type of the microprocessor

                                      Typr of the bus the microprocessor has

                                      Number of CPUs present in the host machine

38. tty :

Command : tty

it displayes the terminal file name

39. date :

Command : date

It displayes the current date and time

40. df :

Command : df

It prints the disk free information in blocks

Command : df –ivt

It prints the disk free information in detail format in blocks

41. dfspace :

Command : /etc/dfspace

It displayes the free disk space  in megabytes(MB)

42. du

Command : du

It displayes the disk usage of the current directory

Command : du /dev

It displaces the disk usage of sub directories in the /dev directory

Command : du –s /dev

It displays the disk space in the /dev directory

43. ulimit(user limit) :

Command : ulimit

It displayes the limit of the file size to be created.

44. passwd :

Command : passwd

By using this command we can change the password

In unix every pass word is stored in the directory /etc/passwd

Example :

$cat  /etc/passwd

Output :

Aa6:x:207:50:user number 6:/usr/aa6:/bin/sh

Here

          Aa6 –login name

          X is for encrypted password

          207 is userid

          50 is groupid

          User number is comment

          /usr/aa6 default working directory

          /bin/sh is for default working shell

45 . cal

Command : cal

 It displayes the callender

Command : cal 2 1997

It displayes the calendar for February 1997

46. banner :

Command : banner string

It displays the string  as a banner.

47. ps(process id )

Command : ps

It prints the process id’s for the current user running on the terminal

Command : ps –a

It prints the process id’s for all the users

Command : ps –u userloginname

It prints the process id’s for the particular user “userloginname”

Command : ps –t terminalname

It prints the process id’s for the particular terminal “ terminalname”

Command : ps –f

It prints the process id’s for the current user in full listing.

Command : ps –e

It prints the process id’d for every process running at that instant

Here –e stands for every process

48. background process :

Command : command   filename > outputfilename&

If u want to run a process in the background we place a ”&” symbol in the end of the command.

Example

Command : sort  employee > emp.out&

Output : 17354(this is the process id)

In this example sort’s the employee data and output is stored in the file emp.out .this process is runs in the back ground .

When we use this command it prints the PID  .

By using this pid we can check where that process is completed or not.

49. nohup :

By using this command we can execute the process with out die even you are logout

Example :

Command : nohup sort employee > outputfile

50. kill :

Command : kill pid

This command kill’s the process

Example

Command : kill 17567

This command kill’s the process 17567

Command : kill -9 2234

This command kill’s the process 2234 forcely.

51 . nice (changing process priority) :

By using nice command we can change the priority of the process execution

The default value for nice command is 20.

We can change the nice values in the ration of 0-19,

Lowest nice values having highest priority and greater nice value having low priority

Example :

                   Nice value=20 is high priority than Nice value =25

To increase the nice value :

Command : nice -10 sort filename > outputfilename

                     Nice value = 20+10 =30

To decrease the nice value:

Command : nice –10 sort filename > outputfilename

                   Nice value = 20-10 =10

To view the nice values:

Command : ps –l

Scheduling :

52 . at

By using this command we can schedule the particular file or particular commands to be execute.

Command : at 5:00pm

Clear > /dev/tty3c

Echo “ hai this is naresh” > /dev/tty3c

Ctrl + d

Output :

Job 3456765.a at Fri jun 5:00 IST 1996

When we execute this command , it schedules the above two commands (clear and echo) these command will execute in the mentioned time

If you did’t give the output as /dev/tty3c is send to the mail

Command : at –r jobid

This commands removes the specified job from the scheduler

Example : at –r 3456765.a

Command : at –l

This commands prints the scheduled jobs

Examples :

Commands :

                   $at 09:15 am Mar 24

                   $at 9:15 am Mar 24

                   $at now +10 minutes

                   $at now + 1 day

                   $at 7 pm Thursday next week

Schedule the file by using at command :

First create a file with required commands

Command : cat >filename

                   Clear

                   Echo “ hai this is naresh”

                   Ctrl d

Now we can schedule this file using at command

Command : at 5:00 < filename

Output : job 39247346.a at Fri Jun 14 5:00 IST 1996

Note :  To use at command our user name must consist in the directory

                   /user/lib/cron/at.allow

          We cannot use the at command if our user name consist in the directory

                   /user/lib/cron/a,deny

53 . batch :

By using this command we can schedule the jobs with out providing the time

UNIX automatically decide when the have to execute 

Command : $batch

                    Clear

                     Echo “ hai this is naresh”

                   Ctrl d

Output :   

               Job 2324234.b at Fri Jun 14 5:00pm IST 1996

54. crontab :

By using this command we can schedule the files with great features

First create a file :

                   Cat > filename

                             30 10 1 * * echo “ work hard for this month”

                             0 10 13 8 * mail aa23 < birthday.file

                             Ctrl d

Command : crontab filename

This file ‘filename”  was executes in the given time

Command : crontab –l

To display the list of crontab files

Command : crontab –r

To remove the crontab entries from scheduler.