NAME
recs-topn
recs-topn --help-all
Help from: --help-basic:
Usage: recs-topn <args> [<files>]
Outputs the top n records from input stream or from <files>. You may segment the input stream based on a list of keys such that
unique values of keys are treated as distinct input streams. This enables top n listings per value groupings. The key values
need not be contiguous in the input record stream.
--key <keyspec> Comma separated list of fields. May be specified multiple times. May be a keyspec or keygroup, see
'--help-keys' for more
--topn | -n <number> Number of records to output. Default is 10.
--delimiter <string> String used internally to delimit values when performing a topn on a keyspec that inlcudeds
multiple keys. This value defaults to "9t%7Oz%]" which may - under unusual and bizarre corner
cases - cause false positive key matches if your values contain this value. You can set this to
any string.
--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-keygroups Help on keygroups, a way of specifying multiple keys
--help-keys Help on keygroups and keyspecs
--help-keyspecs Help on keyspecs, a way to index deeply and with regexes
Examples:
Output just the top 5 records
cat records | recs-topn -n=5
(this is equivalent to executing "cat records | recs-grep '$line < 5'")
Output just 10 records for each area
cat records | recs-sort --key area | recs-topn -n=10 --key area
Output the top 10 longest running queries per area and priority level
cat records | recs-sort --key area,priority,runtime=-n | recs-topn -n=10 --key area,priority
Help from: --help-keygroups:
KEY GROUPS
SYNTAX: !regex!opt1!opt2... Key groups are a way of specifying multiple fields to a recs command with a single argument or
function. They are generally regexes, and have several options to control what fields they match. By default you give a regex,
and it will be matched against all first level keys of a record to come up with the record list. For instance, in a record
like this:
{ 'zip': 1, 'zap': 2, 'foo': { 'bar': 3 } }
Key group: !z! would get the keys 'zip' and 'zap'
You can have a literal '!' in your regex, just escape it with a \.
Normally, key groups will only match keys whose values are scalars. This can be changed with the 'returnrefs' or rr flag.
With the above record !f! would match no fields, but !f!rr would match foo (which has a value of a hash ref)
Options on KeyGroups:
returnrefs, rr - Return keys that have reference values (default:off)
full, f - Regex should match against full keys (recurse fully)
depth=NUM,d=NUM - Only match keys at NUM depth (regex will match against
full keyspec)
sort, s - sort keyspecs lexically
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
- RecordStream(3) - Overview of the scripts and the system
- recs-examples(3) - A set of simple recs examples
- recs-story(3) - A humorous introduction to RecordStream
- SCRIPT --help - every script has a --help option, like the output above