exec - abandon this program to run another


exec LIST


The exec function executes a system command AND NEVER RETURNS, unless the command does not exist and is executed directly instead of via /bin/sh -c (see below). Use system instead of exec if you want it to return.

If there is more than one argument in LIST, or if LIST is an array with more than one value, calls execvp with the arguments in LIST. If there is only one scalar argument, the argument is checked for shell metacharacters. If there are any, the entire argument is passed to /bin/sh -c for parsing. If there are none, the argument is split into words and passed directly to execvp, which is more efficient. Note: exec and system do not flush your output buffer, so you may need to set $| to avoid lost output. Examples:

    exec '/bin/echo', 'Your arguments are: ', @ARGV;
    exec "sort $outfile | uniq";

If you don't really want to execute the first argument, but want to lie to the program you are executing about its own name, you can specify the program you actually want to run as an ``indirect object'' (without a comma) in front of the LIST. (This always forces interpretation of the LIST as a multi-valued list, even if there is only a single scalar in the list.) Example:

    $shell = '/bin/csh';
    exec $shell '-sh';		# pretend it's a login shell

or, more directly,

    exec {'/bin/csh'} '-sh';	# pretend it's a login shell