Dan Track wrote:
Just wondering if you could exaplin something to me:
1) What does the following mean in plain english ^\(Target\[[^]]*\].
I'm getting confused by the number of "[" brackets. To be specific I
can't see how this part \[[^]]*\] is working. The \[ indicates the
match to the "[" string but what I read from [^]] here is that I want
the regular expression to match any of these ^] charaters. But there
isn't a ^ charater or a ].
I'll take it element by element.
^ = Anchor the expression to the start of a line,
\( ... \) = sed "remembers" whatever matches the expression between \(
and \) and will use that text in the replacement part of the
search-and-replace - a "\1" means the first "remembered" text, a "\2"
means the second "remembered" text etc.
Terget = boilerplate text to be matched
\[ = match the literal character "["
[^]] = match any character except "]"
2) What does $!N mean.
I pulled this from the sed FAQ, which explains it better than I could:
http://www.student.northpark.edu/pemente/sed/sedfaq4.html#s4.23.2
Note that the 'N' followed by the 'P;D;' commands forms a "sliding
window" technique. A window of N lines is formed. If the multi-line
pattern matches, the block is handled. If not, the top line is printed
and then deleted from the pattern space, and we try to match at the
next line."
$!N literally means "if we're not at the end of the file, read the next
line into the pattern space"
Paul.
