Basic Linux Tutorial

Computer Tutorial

Introduction to Linux History of Linux Linux distributions Advantages of Linux Difference between Linux and Windows

Linux File System Root Directory Bin Directory Configuration Directories Data Directories Memory Directories Unix System Resources

Basic Linux Commands Login Related Command User Login Related Commands General Orientation Commands

File Managing Commands Working with Directories Working with Files Working with File Contents Filter Commands

File Permission & Access Ownership of Linux files Permissions of Linux files Changing file permissions Absolute or Numeric Mode Symbolic Mode Changing Owners and Groups

Input & Output Redirection Standard Output Redirection Standard Input Redirection Standard Error Redirection

Piping The T-Junction I/O Redirection & Piping

» Other Linux Commands » ARPA Services Commands » Berkeley Services Commands » Process Control Command » Offline file Storage

Vi Editor Modes Used in Vi Editor Starting and Stopping Vi Cursor Movement Inserting and Deleting Text Replacing Text Search and Replace Cut, Copy, and Paste Importing and Exporting Text Configuring Vi Options

Shell Scripting Variables Passing Data Through Environment Variables Special Shell Variables Command Line Arguments The shift Command The read Command The echo Command

Branching The test Command Testing Numeric & String Values Testing Files & Logical Operators The if then fi Structure The if then else fi Structure The case Structure

Loops The let command The while-do-done Loop The until-do-done Loop The for-do-done Loop

Process Control Commands

The ps Command

Every process that is initiated on the system is assigned a unique identification number, known as a process ID (PID ). The ps command displays information about processes currently running (or sleeping) on your system, including the PID of each process and the PID of each process's parent ( PPID). The ps command will also report who owns each process and which terminal each process is executing through.

Synopsis :

$ ps [-efl]

Example :

$ ps
PID TTY TIME COMMAND
1324 ttyp2 0:00 sh
1387 ttyp2 0:00 ps
The -e option reports about every process running on the system, not just your own. The -f and -l options report full and long listings, which include additional detail on the processes.

The nohup Command

the nohup command to make commands immune to hanging up and logging off. The nohup command is one of a group of commands which precede another command.

Synopsis :

nohup command line &

Example :

nohup cat * > bigfile &

The nice Command

The nice command is another prefix command that allows you to execute a program at a lower priority. It is useful when issuing commands whose completion is not required immediately, such as formatting the entire collection of manual pages.

Synopsis :

$nice [-N] command_line
Where N is an integer value between one and nineteen. The default increment is 10. A process with a higher nice value will have a lower relative system priority. The nice value is not an absolute priority modifier.

Example :

$ nice -10 cc myprog.c -o myprog
$ nice -5 sort * > sort.out &

The kill Command

The kill command can be used to terminate any command including nohup and background commands. More specifically, kill sends a signal to a process. The default action for a process is to die when most signals are received. The issuer must be the owner of the target commands; kill cannot be used to kill another user's commands unless the superuser issues it.

Synopsis :

kill [-s signal_name] PID [PID...]

Basic Linux Tutorial

Process Control Commands