Chapter 31. System Interaction

alarm expr

Schedules a SIGALRM signal to be delivered after expr seconds. If expr is zero, cancels a pending timer.

chdir [ expr ]

Changes the working directory. Uses $ENV{HOME} or $ENV{LOGNAME} if expr is omitted.

chroot filename†

Changes the root directory for the process and any future children.

die [ list ]

Prints the value of list to STDERR and exits with value $! || ($? >> 8) || 255. list defaults to Died.

Inside an eval, the error message is stuffed into $@, and the eval is terminated returning undef ; this makes die the way to raise an exception.

exec [ program ] list

Executes the system command in list; does not return. program can be used to explictly designate the program to execute the command.

exit [ expr ]

Exits immediately with the value of expr, which defaults to zero. Calls END routines and object destructors before exiting.


Does a fork syscall. Returns the process id of the child to the parent process (or undef on failure) and zero to the child process.


Returns the current login name as known by the system. If it returns false, use getpwuid.

getpgrp [ pid ]

Returns the process group for process pid. If pid is zero, or omitted, uses the current process.


Returns the process id of the parent process.

getpriority which, who

Returns the current priority for a process, process group, or user. Use getpriority 0,0 to designate the current process.

glob expr

Returns a list of filenames that match the C-shell pattern(s) in expr. Use File::Glob ...

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