NAME
recs-generate
recs-generate --help-all
Help from: --help-basic:
Usage: recs-generate <args> <command> [<files>]
Executes <command> for each record to generate a record stream, which is then
output with a chain link back to the original record.
<command> is executed opened as a command for each record of input (or
records from <files>) with $r set to a App::RecordStream::Record object. The
output lines of each command execution are interpreted as a serialized Recs
records, one per line. Each such line is reconstituted as a
App::RecordStream::Record, and the '_chain' key is added to the record before
it is printed. The value of the '_chain' key is the record that was
originally passed to the eval expression.
For instance. If you did:
recs-generate "recs-fromatomfeed http://...?key=$r->{title}..."
with input that looked like:
{ 'title' : 'foo' }
{ 'title' : 'bar' }
then recs-generate would end up executing:
recs-fromatomfeed http://...?key=foo...
and interpreting the result as a series of new line separated records.
If the result from recs-fromatomfeed was something like:
{ 'title' : 'zip' }
{ 'title' : 'zap' }
then recs-generate would add the chain link so the output would look like:
{ 'title' : 'zip', 'chain' : { 'title' : 'foo' } }
{ 'title' : 'zap', 'chain' : { 'title' : 'foo' } }
Arguments:
--e a perl snippet to execute, optional
--E the name of a file to read as a perl snippet
--M module[=...] execute "use module..." before executing
snippet; same behaviour as perl -M
--m module[=...] same as -M, but by default import nothing
--passthrough Emit input record in addition to generated
records
--keychain <name> Use 'name' as the chain key (default is
'_chain') may be a key spec, see '--help-
keyspecs' for more info
--filename-key|fk <keyspec> Add a key with the source filename (if no
filename is applicable will put NONE)
Help Options:
--help-all Output all help for this script
--help This help screen
--help-keyspecs Help on keyspecs, a way to index deeply and with regexes
Examples:
Chain recs from a feed to recs from a second feed and the print the titles.
recs-fromatomfeed "http://..." | recs-generate "recs-fromatomfeed http://...?key=$r->{title}" | recs-eval 'join(" ", $r->{title}, $r->{chain}->{title})'
Help from: --help-keyspecs:
KEY SPECS
A key spec is short way of specifying a field with prefixes or regular
expressions, it may also be nested into hashes and arrays. Use a '/' to nest
into a hash and a '#NUM' to index into an array (i.e. #2)
An example is in order, take a record like this:
{"biz":["a","b","c"],"foo":{"bar 1":1},"zap":"blah1"}
{"biz":["a","b","c"],"foo":{"bar 1":2},"zap":"blah2"}
{"biz":["a","b","c"],"foo":{"bar 1":3},"zap":"blah3"}
In this case a key spec of 'foo/bar 1' would have the values 1,2, and 3 in
the respective records.
Similarly, 'biz/#0' would have the value of 'a' for all 3 records
You can also prefix key specs with '@' to engage the fuzzy matching logic
Fuzzy matching works like this in order, first key to match wins
1. Exact match ( eq )
2. Prefix match ( m/^/ )
3. Match anywehre in the key (m//)
So, in the above example '@b/#2', the 'b' portion would expand to 'biz' and 2
would be the index into the array, so all records would have the value of 'c'
Simiarly, @f/b would have values 1, 2, and 3
You can escape / with a \. For example, if you have a record:
{"foo/bar":2}
You can address that key with foo\/bar
SEE ALSO
See App::RecordStream for an overview of the scripts and the system
Run
recs examples
or see App::RecordStream::Manual::Examples for a set of simple recs examplesRun
recs story
or see App::RecordStream::Manual::Story for a humorous introduction to RecordStreamEvery command has a
--help
mode available to print out usage and examples for the particular command, just like the output above.