Parsing a latex file in Perl -

apologies basic question!

i want read in latex file (so text basically) , output (say) theorems, in format

\begin{theorem} lines of latex \end{theorem} 

i kind of figured perl right language this!

of course, know basic programming in c++ , java, , virtually no perl.

nonetheless can read in text file, , process line line.

it seems basic way is:

($string =~ /pattern/)  

i started getting confused reading control codes ?,*+,$, etc.

any simple references or links me started?

(i put on here , not tex site, useful reading text files, , not latex!)

if you're on unix-y machine (this includes macs), task small should reach sed first:

$ sed -ne '/^\\begin{theorem}$/,/^\\end{theorem}$/p' doc.tex 

if you're on windows, though, don't sed bundled os, , perl rather easier install aiui, here's equivalent:

> perl -ne 'print if /^\\begin\{theorem\}$/.../^\\end\{theorem\}$/;' doc.tex 

you may notice distinct resemblance between these 2 commands. that's not accident; perl took ideas many of older unix text-munging utilities, sed included.