Running shell commands in .php file from command-line

Question

I have a series of shell commands I want to put in a program and execute the program from the command line. I decided to use PHP for this so currently I am trying to get the most basic shell commands to run.

Save as build.php

<?php
shell_exec('cd ..');
echo "php executed\n";
?>

From the command-line

php build.php

Output

php executed

Php executes correctly but I'm still in the same directory. How do I get shell_exec( ... ) to successfully call a shell command?

Answer 1

You need to change the cwd (current working directory) in PHP... any cd command you execute via exec() and its sister functions will affect ONLY the shell that the exec() call invokes, and anything you do in the shell.

<?php
    $olddir = getcwd();
    chdir('/path/to/new/dir');  //change to new dir
    exec('somecommand');

will execute somecommand in /path/to/new/dir . If you do

<?php
    exec('cd /path/to/new/dir');
    exec('somecommand');

somecommand will be executed in whatever directory you started the PHP script from - the cd you exec'd just one line ago will have ceased to exist and is essentially a null operation.

Note that if you did something like:

<?php
    exec('cd /path/to/new/dir ; somecommand');

then your command WOULD be executed in that directory... but again, once that shell exits, the directory change ceases to exist.