![ Dd
This command copies files and coverts them in one
format to another.
General format is,
dd [options =values]
Where options can be,
If input filename
Of output filename
Conv file conversion specificatiton.
The value for this option may be
Lcase ,ucase,ascii and abcdic](https://image.slidesharecdn.com/linuxcommandspart3-170514074602/85/Linux-commands-part3-2-320.jpg)
![ Expand
This command converts all the tabs present in the
specified file into blank spaces and displays the
results on the screen.
Expand [-i] <filename>
Where the –i option converts only the intial tab into
blank spaces.
Nl
This command numbers all non blank lines in the
specified text file and displays the same on the
screen.
General format is,
nl <filename>](https://image.slidesharecdn.com/linuxcommandspart3-170514074602/85/Linux-commands-part3-3-320.jpg)
![ Kill
If you want a command to terminate prematurely
press[ctrl+c].
This type of interrupt characters doesnot affect the
background processes because the background
processes are protected by shell from these
interrupt signals.
This kill command is used to terminate a background
process,
General format,
Kill [-signal Number] <PID>](https://image.slidesharecdn.com/linuxcommandspart3-170514074602/85/Linux-commands-part3-9-320.jpg)
Linux commands part3
- 1. PROCESS ORIENTED COMMANDS LINUX COMMANDS : PART 3 1Bhat vijettha
- 2. Dd This command copies files and coverts them in one format to another. General format is, dd [options =values] Where options can be, If input filename Of output filename Conv file conversion specificatiton. The value for this option may be Lcase ,ucase,ascii and abcdic
- 3. Expand This command converts all the tabs present in the specified file into blank spaces and displays the results on the screen. Expand [-i] <filename> Where the –i option converts only the intial tab into blank spaces. Nl This command numbers all non blank lines in the specified text file and displays the same on the screen. General format is, nl <filename>
- 4. Tac This command reverses a file so that last line becomes the first line. General format is, Tac <filename> Tail This command displays the end of the specified file. general format is, Tail +n <filename> +n is used to display the nth line till end of the file . -n last n lines are displayed. No option is used then last 10 lines are displayed.
- 5. Process oriented commands A process is a job in execution. There is a program called scheduler always running in memory which decides which process should get the cpu time and when. Only one process will be executed at a time,because the system has only one processor.
- 6. Ps This command is used to know which process is running at our terminal. General format is, ps –a:this command lists the processes of all the users who are logged on the system. ps-t <terminal_name>:this command lists the processes ,which are running on the specified terminal. <terminal_name>.
- 7. Ps –u<user name>: This command lists the processes, which are running for running for specified user-<username>. Ps –x:this command lists the system processes. Apart from the processes that are generated by the user,there are some processes that keep on running all the time.these processes are called system processes . Examples: $ps $ps –a
- 8. Background processing Linux provides the facility for background processing. when one process is running in the foreground,another process can be executed in the background. Example: $sort emp.doc& By the execution of this command a number is displayed..this is called PID(process identification number).
- 9. Kill If you want a command to terminate prematurely press[ctrl+c]. This type of interrupt characters doesnot affect the background processes because the background processes are protected by shell from these interrupt signals. This kill command is used to terminate a background process, General format, Kill [-signal Number] <PID>
- 10. Examples: $skill 120 This command terminate the process who has the PID 120. $kill -9 130 $kill -9 0 This command kills the processes including the login shell.
- 11. Nohup If a user wants a process that he has executed not to die even when he logged out from the system you can use this nohup command. Normally all the processes of a user are terminated if he logs out. General format is, Nohup <command>&
- 12. Batch This command is used to execute the specified commands when the system load permits (when cpu becomes nearly free). General format is, batch <commands> ^d Any job scheduled with batch also goes to the at queue ,you can list or delete them through atq and atrm respectively.
- 13. Cont…part4