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Stderr Checking In Pipes (trypipeerr)

Laurence MorganAbout 1 minBuiltin CommandsError Handling

Stderr Checking In Pipes (trypipeerr)

Checks state of each function in a pipeline and exits block on error

Description

trypipeerr checks the state of each function and exits the block if any of them fail. Where trypipeerr differs from regular tryerr blocks is trypipeerr will check every process along the pipeline as well as the terminating function (which tryerr only validates against). The downside to this is that piped functions can no longer run in parallel.

Usage

trypipeerr { code-block } -> <stdout>

<stdin> -> trypipeerr { -> code-block } -> <stdout>

Examples

trypipeerr {
    out "Hello, World!" -> grep: "non-existent string" -> cat
    out "This command will be ignored"
}

Formated pager (less) where the pager isn't called if the formatter (pretty) fails (eg input isn't valid JSON):

func pless {
    -> trypipeerr { -> pretty -> less }
}

Detail

A failure is determined by:

  • Any process that returns a non-zero exit number
  • Any process that returns more output via stderr than it does via stdout

You can see which run mode your functions are executing under via the fid-list command.

See Also


This document was generated from builtins/core/structs/tryerr_doc.yamlopen in new window.

Last update:
Contributors: Laurence Morgan