filter-with-sah - Filter data


This document describes version 0.482 of filter-with-sah (from Perl distribution App-SahUtils), released on 2022-09-30.


filter-with-sah [--compiler=str|-C=str] [(--config-path=path)+|--no-config] [--config-profile=profile|-P] [--data-as-json=str] [--data-as-perl=str] [--data-with-result|-d] [--filter-names=any|--filter-names-json=json] [--format=name|--json] [--linenum|-l] [--multiple-data-as-json=str] [--multiple-data-as-perl=str] [--(no)naked-res] [--no-env] [--page-result[=program]|--view-result[=program]] [--return-type=str|-r=str] [--show-code|-c]


* marks required options.

Action selection options

--show-code, -c

Don't filter data, show generated filter code only.

Configuration options


Set path to configuration file.

Can actually be specified multiple times to instruct application to read from multiple configuration files (and merge them).

Can be specified multiple times.

--config-profile=s, -P

Set configuration profile to use.

A single configuration file can contain profiles, i.e. alternative sets of values that can be selected. For example:


When you specify --config-profile=dev, username will be set to foo and password to beaver. When you specify --config-profile=production, username will be set to bar and password to honey.


Do not use any configuration file.

If you specify --no-config, the application will not read any configuration file.

Data specification options


Data as JSON.


Data as Perl code.


Multiple data as JSON code, JSON data must be an array.


Multiple data as Perl code, perl code should return arrayref.

Environment options


Do not read environment for default options.

If you specify --no-env, the application wil not read any environment variable.

Filter specification options

--compiler=s, -C

Select compiler.

Default value:


Valid values:


See --filter-names.

--return-type=s, -r

Default value:


Valid values:


Output options

--data-with-result, -d

Show data alongside with filtered result.

The default is to show the filtered result only.


Choose output format, e.g. json, text.

Default value:


Output can be displayed in multiple formats, and a suitable default format is chosen depending on the application and/or whether output destination is interactive terminal (i.e. whether output is piped). This option specifically chooses an output format.


Set output format to json.

--linenum, -l

When showing source code, add line numbers.


When outputing as JSON, add result envelope.

By default, when outputing as JSON, the full enveloped result is returned, e.g.:


The reason is so you can get the status (1st element), status message (2nd element) as well as result metadata/extra result (4th element) instead of just the result (3rd element). However, sometimes you want just the result, e.g. when you want to pipe the result for more post-processing. In this case you can use --naked-res so you just get:


Filter output through a pager.

This option will pipe the output to a specified pager program. If pager program is not specified, a suitable default e.g. less is chosen.


View output using a viewer.

This option will first save the output to a temporary file, then open a viewer program to view the temporary file. If a viewer program is not chosen, a suitable default, e.g. the browser, is chosen.

Other options

--help, -h, -?

Display help message and exit.

--version, -v

Display program's version and exit.


This script has shell tab completion capability with support for several shells.


To activate bash completion for this script, put:

 complete -C filter-with-sah filter-with-sah

in your bash startup (e.g. ~/.bashrc). Your next shell session will then recognize tab completion for the command. Or, you can also directly execute the line above in your shell to activate immediately.

It is recommended, however, that you install modules using cpanm-shcompgen which can activate shell completion for scripts immediately.


To activate tcsh completion for this script, put:

 complete filter-with-sah 'p/*/`filter-with-sah`/'

in your tcsh startup (e.g. ~/.tcshrc). Your next shell session will then recognize tab completion for the command. Or, you can also directly execute the line above in your shell to activate immediately.

It is also recommended to install shcompgen (see above).

other shells

For fish and zsh, install shcompgen as described above.


When there is an error (e.g. in generating filter code, in filtering) the program returns undef/null, how do I see the error message?

Pass `--no-naked-res` to see the error code and error message. The default is naked for simpler output.


This script can read configuration files. Configuration files are in the format of IOD, which is basically INI with some extra features.

By default, these names are searched for configuration filenames (can be changed using --config-path): /home/u1/.config/filter-with-sah.conf, /home/u1/filter-with-sah.conf, or /etc/filter-with-sah.conf.

All found files will be read and merged.

To disable searching for configuration files, pass --no-config.

You can put multiple profiles in a single file by using section names like [profile=SOMENAME] or [SOMESECTION profile=SOMENAME]. Those sections will only be read if you specify the matching --config-profile SOMENAME.

You can also put configuration for multiple programs inside a single file, and use filter program=NAME in section names, e.g. [program=NAME ...] or [SOMESECTION program=NAME]. The section will then only be used when the reading program matches.

You can also filter a section by environment variable using the filter env=CONDITION in section names. For example if you only want a section to be read if a certain environment variable is true: [env=SOMEVAR ...] or [SOMESECTION env=SOMEVAR ...]. If you only want a section to be read when the value of an environment variable equals some string: [env=HOSTNAME=blink ...] or [SOMESECTION env=HOSTNAME=blink ...]. If you only want a section to be read when the value of an environment variable does not equal some string: [env=HOSTNAME!=blink ...] or [SOMESECTION env=HOSTNAME!=blink ...]. If you only want a section to be read when the value of an environment variable includes some string: [env=HOSTNAME*=server ...] or [SOMESECTION env=HOSTNAME*=server ...]. If you only want a section to be read when the value of an environment variable does not include some string: [env=HOSTNAME!*=server ...] or [SOMESECTION env=HOSTNAME!*=server ...]. Note that currently due to simplistic parsing, there must not be any whitespace in the value being compared because it marks the beginning of a new section filter or section name.

To load and configure plugins, you can use either the -plugins parameter (e.g. -plugins=DumpArgs or -plugins=DumpArgs@before_validate_args), or use the [plugin=NAME ...] sections, for example:



which is equivalent to setting -plugins=-DumpArgs@before_validate_args@99,-Foo@after_validate_args,arg1,val1,arg2,val2.

List of available configuration parameters:

 compiler (see --compiler)
 data_as_json (see --data-as-json)
 data_as_perl (see --data-as-perl)
 data_with_result (see --data-with-result)
 filter_names (see --filter-names)
 format (see --format)
 linenum (see --linenum)
 multiple_data_as_json (see --multiple-data-as-json)
 multiple_data_as_perl (see --multiple-data-as-perl)
 naked_res (see --naked-res)
 return_type (see --return-type)
 show_code (see --show-code)



String. Specify additional command-line options.






Please visit the project's homepage at


Source repository is at


perlancar <>


To contribute, you can send patches by email/via RT, or send pull requests on GitHub.

Most of the time, you don't need to build the distribution yourself. You can simply modify the code, then test via:

 % prove -l

If you want to build the distribution (e.g. to try to install it locally on your system), you can install Dist::Zilla, Dist::Zilla::PluginBundle::Author::PERLANCAR, Pod::Weaver::PluginBundle::Author::PERLANCAR, and sometimes one or two other Dist::Zilla- and/or Pod::Weaver plugins. Any additional steps required beyond that are considered a bug and can be reported to me.


This software is copyright (c) 2022, 2020, 2019, 2018, 2017, 2016, 2015 by perlancar <>.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.


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When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.