( string command, string mode )
Opens a pipe to a process executed by forking the command given
Returns a file pointer identical to that returned by
fopen(), except that it is unidirectional (may
only be used for reading or writing) and must be closed with
pclose(). This pointer may be used with
fgets(), fgetss(), and
If an error occurs, returns FALSE.
If you're looking for bi-directional support (two-way), use
Example 1. popen() example
$handle = popen("/bin/ls", "r");
If the command to be executed could not be found, a valid
resource is returned. This may seem odd, but makes sense; it
allows you to access any error message returned by the shell:
/* Add redirection so we can get stderr. */
$handle = popen('/path/to/spooge 2>&1', 'r');
echo "'$handle'; " . gettype($handle) . "\n";
$read = fread($handle, 2096);
safe mode is enabled, you can only
execute executables within the safe_mode_exec_dir.
For practical reasons it is currently not allowed to have ..
components in the path to the executable.
With safe mode enabled,
the command string is escaped with escapeshellcmd(). Thus,
echo y | echo x becomes echo y \| echo x.
See also pclose(), fopen(),