sed awk to perl help

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

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Re: sed awk to perl help by Corion (Patriarch) on Apr 17, 2007 at 08:42 UTC
You're on the right track already, except that variable names in Perl are prefixed by a sigil - `$` is the sigil for a single value, while `@` is the sigil for an array/a list, and `%` is the sigil for a hash ("associative array" in awk). For a start, I'd just convert the stuff behind the `cat` invocation verbatim which is the trickier part: `use strict; # Read from standard input while (<>) { s/;/\n/g; # this is just like sed s/:/\n/g; # this is just like sed # Now, split the input line on newlines, like awk will do: my @pages = split /\n/; for my $page (@pages) { # I'm using qq{...} instead of double quotes (") # so I don't have to escape the stuff in ugly ways print qq{<a href="http://mysite.net/$page">$page</a>\n}; }; };` [download] To convert the two verbatim sed commands and the awk command into one thing that just takes everything that is delimited by `;` or `:` and prints out a HTML link to it, I'd rewrite the loop as follows: `use strict; # Read from standard input while (<>) { # Remove the newline at the end of $_ chomp; # Split the input line on ":" or ";": my @pages = split /[:;]/; for my $page (@pages) { # I'm using qq{...} instead of double quotes (") # so I don't have to escape the stuff in ugly ways print qq{<a href="http://mysite.net/$page">$page</a>\n}; }; };` [download] Update: Replaced my erroneous use of `$1` with `$page`, which is the correct variable to use. Thanks, johngg!	[reply] [d/l] [select]
Re^2: sed awk to perl help by johngg (Canon) on Apr 17, 2007 at 08:54 UTC
Perhaps I'm missing something but how is the `$l` (or is it `$1`) in the `print` statements getting initialised. Maybe it should be `$page` in each case? Cheers, JohnGG	[reply] [d/l] [select]
Re: sed awk to perl help by Limbic~Region (Chancellor) on Apr 17, 2007 at 10:34 UTC
Anonymous Monk, Beyond the advice you have already been given, your perl should have shipped with a s2p and a2p utility. Even if you do not use the resulting code, it should give you a good idea of one way to do it. Cheers - L~R	[reply]
Re: sed awk to perl help by Moron (Curate) on Apr 17, 2007 at 15:48 UTC
For replacing this type of "one-liner" shell processing containing invocations of awk and sed with equivalent Perl code, I strongly suggest looking at perlrun. In this example it becomes something like: `perl -pipage.txt -ea -F"[;:]" 'my $out=shift @F;print "<a href=mysite. +net/$out>$out</a>\n";'` [download] __________________________________________________________________________________ ^M Free your mind!	[reply] [d/l]
Re^2: sed awk to perl help by dcd (Scribe) on Apr 17, 2007 at 21:06 UTC
When I tried this example, I had some problems with it, and I think there are 2 issues: 1) the order of the arguments (I needed to order them as `perl -paipage.txt -F"[;:]" -e` to avoid the error `Can't open my $out=shift @F;print "<a href=mysite.net/$out>$out</a>\n" +;: No such file or directory.` [download] and 2), the script didn't seem to handle multiple matches on the same line (that I think the original did) `'map { print "<a href=mysite.net/$_>$_</a>\n" } @F'` then I realized that this still didn't handle the way that awk deals with white space, so the one line got longer when I added `split(" ",$_)` `perl -F"[:;]" -lane 'map { ($_)=split " ",$_; print "<a href=mysite.ne +t/$_ >$_</a>" } @F'` [download] given test data like `a b ; d e : f g : ; x` [download]	[reply] [d/l] [select]
Re^3: sed awk to perl help by Moron (Curate) on Apr 17, 2007 at 21:29 UTC
the -F specifies the split pattern, so instead of also splitting by ' ', just change the -F argument to `-F"[:;\s]"` __________________________________________________________________________________ ^M Free your mind! Key to hats: ^I=white ^B=black ^P=yellow ^E=red ^C=green ^M=blue - see Moron's scratchpad for fuller explanation.	[reply] [d/l]
Re^4: sed awk to perl help by dcd (Scribe) on Apr 18, 2007 at 01:50 UTC
Re^5: sed awk to perl help by Moron (Curate) on Apr 18, 2007 at 11:37 UTC
Re: sed awk to perl help by xicheng (Sexton) on Apr 18, 2007 at 05:10 UTC
From your pipe line, I guess you actually want to grab the first 'word' (any continuous non whitespaces\|simicolon\|colon, like [^\s;:]+) after the start of a newline '^' or any colon\|simicolon characters. This can be done pretty easily by a regex, not necessarily a better way, just another option for you: perl -wlne ' my @sites = /(?:^\|[;:])\s*([^\s:;]+)/g; print qq(<a href="mysite.net/$_" >$_</a>) for @sites; ' page.txt Regards, Xicheng	[reply]