---
name: "Schedule::At"
section: "3pm"
platform: "linux"
package: "libschedule-at-perl"
version: "1.15-1.1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Schedule::At"
---

# Schedule::At(3pm)

OS independent interface to the Unix 'at' command

## NAME

Schedule::At - OS independent interface to the Unix 'at' command

## SYNOPSIS

```
 require Schedule::At;
 Schedule::At::add(TIME => $string, COMMAND => $string [, TAG =>$string]);
 Schedule::At::add(TIME => $string, COMMAND => \@array [, TAG =>$string]);
 Schedule::At::add(TIME => $string, FILE => $string)
 %jobs = Schedule::At::getJobs();
 %jobs = Schedule::At::getJobs(JOBID => $string);
 %jobs = Schedule::At::getJobs(TAG => $string);
 Schedule::At::readJobs(JOBID => $string);
 Schedule::At::readJobs(TAG => $string);
 Schedule::At::remove(JOBID => $string);
 Schedule::At::remove(TAG => $string);
```

## DESCRIPTION

This modules provides an OS independent interface to 'at', the Unix  command that allows you to execute commands at a specified time.

- Schedule::At::add

  Adds a new job to the at queue.

  You have to specify a **TIME** and a command to execute. The **TIME** has a common format: YYYYMMDDHHmm where **YYYY** is the year (4 digits), **MM** the month (01-12), **DD** is the day (01-31), **HH** the hour (00-23) and **mm** the minutes.

  The command is passed with the **COMMAND** or the **FILE** parameter. **COMMAND** can be used to pass the command as an string, or an array of commands, and **FILE** to read the commands from a file.

  The optional parameter **TAG** serves as an application specific way to  identify a job or a set of jobs.

  Returns 0 on success or a value != 0 if an error occurred.

- Schedule::At::readJobs

  Read the job content identified by the **JOBID** or **TAG** parameters.

  Returns a hash of JOBID =\> `$string` where `$string` is the the job content. As the operating systems usually add a few environment settings, the content is longer than the command provided when adding the job.

- Schedule::At::remove

  Remove an at job.

  You identify the job to be deleted using the **JOBID** parameter (an  opaque string returned by the getJobs subroutine). You can also specify a job or a set of jobs to delete with the **TAG** parameter, removing all the jobs that have the same tag (as specified with the add subroutine).

  Used with JOBID, returns 0 on success or a value != 0 if an error occurred. Used with TAG, returns a hash reference where the keys are the JOBID of the jobs found and the values indicate the success of the remove operation.

- Schedule::At::getJobs

  Called with no params returns a hash with all the current jobs or  dies if an error has occurred.  It's possible to specify the **TAG** or **JOBID** parameters so only matching jobs are returned. For each job the key is a JOBID (an OS dependent string that shouldn't be  interpreted), and the value is a hash reference.

  This hash reference points to a hash with the keys:

  - TIME

    An OS dependent string specifying the time to execute the command

  - TAG

    The tag specified in the Schedule::At::add subroutine

## Configuration Variables

- •

  `$Schedule::At::SHELL`

  This variable can be used to specify shell for execution of the scheduled command. Can be useful for example when scheduling from CGI script and the account of the user under which httpd runs is locked by using '/bin/false' or similar as a shell.

## EXAMPLES

```
 use Schedule::At;
 # 1
 Schedule::At::add (TIME => '199801181530', COMMAND => 'ls',
        TAG => 'ScheduleAt');
 # 2
 @cmdlist = ("ls", "echo hello world");
 Schedule::At::add (TIME => '199801181630', COMMAND => \@cmdlist,
        TAG => 'ScheduleAt');
 # 3
 Schedule::At::add (TIME => '199801181730', COMMAND => 'df');
 # This will remove #1 and #2 but no #3
 Schedule::At::remove (TAG => 'ScheduleAt');
 my %atJobs = Schedule::At::getJobs();
 foreach my $job (values %atJobs) {
        print "\t", $job->{JOBID}, "\t", $job->{TIME}, ' ',
                ($job->{TAG} || ''), "\n";
 }
```

## AUTHOR

Jose A. Rodriguez (jose AT rodriguez.jp)