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@@ -12,9 +12,79 @@ .Nm .Fl h .Sh DESCRIPTION +The +.Nm +utility searches for text in files corresponding to +.Ar pattern +and prints the corresponding matches to the standard output. +Unlike the +.Xr grep 1 +utility, +.Nm +is not strictly line-oriented; +instead of always matching on complete lines, +the user defines the structure of the text they would like to match and +filters on the results. +For more details on the pattern syntax, see +.Sx Pattern Syntax . +.Pp +.Nm +will read from the files provided on the command-line. +If no files are provided, the standard input will be read instead. +The special filename +.Sq - +can also be provided, +which represents the standard input. +.Pp +The options are as follows: +.Bl -tag -width Ds +.It Fl h +Display help information by opening this manual page. +.It Fl z +Separate output data by null bytes +.Pq Sq \e0 +instead of newlines. +This option can be used to process matches containing newlines. +.El +.Ss Pattern Syntax +A pattern is a sequences of commands optionally separated by whitespace. +A command is an operator followed by a delimiter, a regular expression, +and then terminated by the same delimiter. The last command of a pattern +need not have a terminating delimiter. +.Pp +The supported operators are as follows: +.Bl -tag -compact +.It g +Keep selections that match the given regex. +.It v +Discard selections that match the given regex. +.It x +Select everything that matches the given regex. +.It y +Select everything that doesn’t match the given regex. +.El +.Pp +An example pattern to match all numbers that contain a ‘3’ but aren’t +‘1337’ could be +.Sq x/[0-9]+/ g/3/ v/^1337$/ . +In that pattern, +.Sq x/[0-9]+/ +selects all numbers in the input, +.Sq g/3/ +keeps only those matches that contain the number 3, +and +.Sq v/^1337$/ +filters out the specific number 1337. +.Pp +As you may use whichever delimiter you like, the following is also valid: +.Pp +.Dl x|[0-9]+| g.3. v#^1337# .Sh EXIT STATUS .Ex -std .Sh EXAMPLES +List all your systems CPU flags, sorted and without duplicates: +.Pp +.Dl $ grab 'x/^flags.*/ x/\ew+/ v/flags/' | sort | uniq .Sh SEE ALSO .Xr grep 1 .Rs |