Linux command and PHP

In Operating systems either it is linux, unix or windows system, there are programs which are running on background to keep system functional, these programs are called processes. in linux or unix like systems we have ps command to view processes running on system.
ps command is used to check currently running process status on linux or unix systems. To execute this command just type ps and enter you will have all the currently running process.

$ ps
 PID  TT  STAT      TIME COMMAND
 1175  v0  Is+    0:00.00 /usr/local/man/ps
 1176  v1  Is+    0:00.00 /usr/bin/prox
 63552   0  R+     0:00.00 ps

If you have something wrong or problem from any process you can kill that process from knowing his process id and type command

 $ kill 1175
 $ kill 1175 1176 # for multiple killing process
 

All linux command has many options to display the description that we can view by man command.
Suppose we have to view the process for some specific user.

 $ man ps # display command description
 $ ps –auwx | grep xyz_user | grep php
 xyz_user  1302  0.0  1.0 60804 10140  ??  I     4Apr12   0:01.65 /usr/local/bin/php /usr/local/www/apache/phpCli.php
 xyz_user  7471  0.0  1.0 60804 10516  ??  I    Wed11AM   0:01.12 /usr/local/bin/php /usr/local/www/apache2/commxyz.php

Above ps command show how can we do pattern searching with the help of grep command, here we search all the currently running process for specific user and having matched string ‘php’ . In result we get PHP files for that specific user running on system along with process id, time and path of that file.

Let’s try now second command to view process, top: its show all running top process like in windows we watch process in “Task manager” process. Simple we can get this by top in linux.

 $ top
 last pid: 72169;  load averages:  0.00,  0.01,  0.00 up 12+22:19:36  10:29:31
 59 processes:  1 running, 58 sleeping
 CPU:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% idle
 Mem: 114M Active, 524M Inact, 216M Wired, 41M Cache, 111M Buf, 56M Free
 Swap: 2011M Total, 220K Used, 2011M Free
 PID USERNAME       THR PRI NICE   SIZE    RES STATE   C   TIME   WCPU COMMAND
 70726 www              1  45    0   131M 18188K select  1   0:02  0.29% httpd
 1025 pgsql            1  44    0 23820K  4444K select  0   2:11  0.00% postgres
 1022 pgsql            1  44    0 64132K 16032K select  1   1:17  0.00% postgres
 1053 root             1  44    0   129M 12848K select  1   0:26  0.00% httpd
 

This top command result so many information like last processed id, load average of system, uptime, CPU States, memory and swap. If you watch out the screen, you must view the processes running currently and all his information as PID, username time CPU usage etc.

Now if you want these commands to run from php script, there are many php inbuilt function to execute linux commands like exec, system, passthru, shell_exec , backtick operator (` `) etc. we can try any of these to execute linux command by php.
Suppose we have to execute above process command by command line script

 // create a variable
 $ps_cmd = "ps -auwx | grep xyz_user| grep php";
 // execute by backtick operator
 $ps_exec = `$ps_cmd`;
 // output
 var_dump($ps_exec);
 OR
 $psexc = exec($ps_cmd, $ps_output, $ps_result);
 var_dump($ps_output);
 var_dump($ps_result);
 

This will output as same above all the currently running process for specific user and having matched string ‘php’. In case of using backtick operator we get above result. Using exec we get output in two parameter: output and result. output gives an array and result give either command executes successfully or not.

3 Responses to Linux command and PHP

  1. parveen says:

    Dear Alok,

    I would like to know whether the process is running in background or foreground.

  2. raj says:

    can u post more command that is running in background………….

    if u post such kind of information. i’ll explore your site again…………

    thanks

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