Shell Programming and Scripting

Originally Posted by durden_tyler

awk splits up the input line into tokens $1, $2, $3, ... etc.; so for this line

Code:

MODStandard , Building=3A 1234, Syntax ID=3B=

$4 equals the string "1234,".

awk's "sub" function performs a replacement on a target string. So

Code:

sub(/,/,"",$4);

replaces the comma (in the regex pattern /,/) by zero-length string (2nd argument "") in the target string $4 (which is "1234,"). Thus $4 turns into "1234" which is then printed.

The construct

Code:

/Building/ {<action>}

performs the action <action> only for lines that have the literal "Building" in them.

A Perl one-liner for the same problem would be:

Code:

$
$ cat f2
blah
MODStandard , Building=3A 1234, Syntax ID=3B=
blah blah
$
$ perl -lne '/Building.*? (\d+),/ and print $1' f2
1234
$
$

HTH,
tyler_durden