debug
Operator
debug — write intermediate values to stderr
Synopsis
debug [ <expr> ]
Description
The debug operator writes the value of expr to the debug channel. If no
expr is provided, this is written to the debug channel. If the query is
run on the command line via zq or zed all output written to the debug
channel is displayed on stderr.
The debug operator is useful to view intermediate values when debugging a
complex Zed query.
If used more than once within a single Zed program, the relative order of
outputs in the debug channel from each separate debug invocation is
undefined.
Examples
The following query uses expressions containing f-strings
to display "debug: foo" on stderr whereas "foo_bar" will display
on stdout.
echo '"foo"' | zq -z 'debug f"debug: {this}" | yield f"{this}_bar"' -