http://www.gnu.org/software/bash/manual/bashref.html#Shell-Parameter-Expansion

t='main.exe' ; echo ${t/.exe/}
#| main

echo ${EMAIL/@/(a)}
echo ${PWD// /_} 

echo ${OSTYPE}
# linux-gnu
echo ${OSTYPE/-/_}
# linux_gnu

echo ${OSTYPE%-gnu}
echo ${OSTYPE%-*}
# linux

parameter substitutions ${-=?+}

echo ${OS:=unix}

@tag: bash sh

${SRCS:.cpp=.o}

echo " match \"what\" is \"inside quotes\" only " | grep -o '"[^\"]*"'

echo " match \"what\" is \"inside quotes\" only " | sed 's/"[^\"]*"/\n&\n/g' | grep  ^\"
"what"
"inside quotes"

EmacS

http://www.gnu.org/software/libtool/manual/emacs/Regexp-Replace.html

M-x replace-regex
mailto:.*@\(.*\) 
host:\1

\[.*\] []

Vi:

Replace ^M in vim :

%s/\r//g

• http://www.perl.com/doc/manual/html/pod/perlre.html

$html='<img src="foo" >';
preg_match_all("|<img src=\"([^\"]*)\".*|", $html , $url );
print_r( $url );
print ( "url=" . $url[1][0] . "\n" ); // url=foo

eregi("MSIE", $HTTP_USER_AGENT);

• http://www.diveintopython.org/regular_expressions/street_addresses.html

thx to pok

#!/usr/bin/env ruby

puts ABOUT = "There are my git repositories"
puts "=" * ABOUT.size
puts
puts "[in #{HERE = File.dirname(__FILE__)}]"
puts

Dir["#{HERE}/**/.git"].each do |g| 
  puts "* #{g.gsub(%r{^#{HERE}/}, '').gsub(%r{/\.git$}, '')}"
end

puts

s="a\n\r\n\rb\r\r\rc\n\n\rd";
document.write("#s=\""+s+"\"");
m=/\r+/g; 
r="\n"; 
s=s.replace(m,r); 
r="_";
m=/\n+/g; 
s=s.replace(m,r); 

• http://www.ex-parrot.com/~pdw/Mail-RFC822-Address.html
• http://www.regexlib.com/REDetails.aspx?regexp_id=711
• http://www.weitz.de/regex-coach/#install ClosedSource Linux Windows

ed2k://|file|regex-coach.tgz|2505734|599b0466ada8e0f4361f3d7d8d85f249|

# function to parse ini file (backup.ini)
#
# $1 -> file.ini
# $2 -> section
_parse_ini () {
   if [ -z "$1" ] || [ -z "$2" ]; then return 0; fi
   eval `cat $1 | \
      sed -e 's/[[:space:]]*\=[[:space:]]*/=/g' \
      -e 's/;.*$//' \
      -e 's/[[:space:]]*$//' \
      -e 's/^[[:space:]]*//' \
      -e "s/^\(.*\)=\([^\"']*\)$/\1=\"\2\"/" | \
      sed -n -e "/^\[$2\]/,/^\s*\[/{/^[^;].*\=.*/p;}"`

}

• http://packages.qa.debian.org/r/rpl.html
• http://www.amk.ca/python/howto/regex/
• http://sitescooper.org/tao_regexps.html
• http://www.english.uga.edu/humcomp/perl/regex2a.html
• http://www.english.uga.edu/humcomp/perl/regexps.html
• http://www.english.uga.edu/humcomp/perl/regular_expressions.HTML
• http://www.english.uga.edu/humcomp/perl/
• http://java.sun.com/docs/books/tutorial/extra/regex/
• http://gnosis.cx/publish/programming/regular_expressions.html
• http://www.zvon.org/other/PerlTutorial/Books/Book1/
• http://it.metr.ou.edu/regex/
• http://www.regular-expressions.info/
• http://matt.might.net/articles/sculpting-text/

@TaG: regular expression Perl Unix Shell VI bash sed awk php