How to use the command `sattach` (with examples)

The sattach command is used to attach to a Slurm job step. It allows users to redirect the IO streams (stdout, stderr, and stdin) of a Slurm job step to the current terminal. This can be useful for monitoring and interacting with the running job.

Use case 1: Redirect the IO streams of a Slurm job step to the current terminal

Code:

sattach jobid.stepid

Motivation: Redirecting the IO streams of a Slurm job step to the current terminal allows users to monitor the progress of the job in real-time. It provides a convenient way to view the output and error messages generated by the job, as well as interact with it if necessary.

Explanation:

• jobid.stepid: Specifies the job and step ID to attach to. The jobid refers to the job ID of the Slurm job, and the stepid refers to the specific step within the job.

Example output:

Attaching to job 12345.step1

Use case 2: Use the current console’s input as stdin to the specified task

Code:

sattach --input-filter task_number

Motivation: Using the current console’s input as stdin to the specified task allows users to provide input to the task in real-time. This can be helpful for tasks that require user interaction or dynamic input.

Explanation:

• --input-filter task_number: Specifies the task number to attach to. The task_number refers to the specific task within the Slurm job.

Example output:

- Input received from console is being redirected to task 2 -

Use case 3: Only redirect stdin/stderr of the specified task

Code:

sattach --output|error-filter task_number

Motivation: Redirecting only stdin or stderr of the specified task can be useful in scenarios where the user only wants to monitor specific aspects of the task. This allows for a more focused analysis of the job’s output and error messages.

Explanation:

• --output|error-filter task_number: Specifies the task number to attach to and the type of stream to redirect. The task_number refers to the specific task within the Slurm job, and the output|error-filter allows for selecting either stdout or stderr.

Example output:

- Only stdout of task 3 is being redirected -

Conclusion:

The sattach command provides a flexible way to monitor and interact with Slurm job steps. By redirecting the IO streams or using the console’s input, users can effectively monitor the progress of their jobs, provide dynamic input, and focus on specific aspects of the job’s output and error messages.