Shell Programming and Scripting

Code:

sed -n '1h;1d;/:/ba;H;$!d;:a;x;s/\n/ /g;p;' infile

I believe everyone is entitled to beautified code -- it prevents mistakes. A sed looper should not try to filter-transform, because lines arrive in two or more places. You can just pipe one sed to the next. The big trick to sed is regex, learning how to tame the hungry wild card .* by either tying it to the end of line to find the first: ' .*$' or by using a value-restricted list: '^[^ ]* '. Then you can delineate the area you need to substring with \(\) which become \1-\9. The regex skills are useful in vi, ex, C/C++, PERL, awk, ksh command line editing. The regex meta-character set varies by situation and age/source of library, expanding in sed in one direction and in egrep in another direction. You can find the basics here with man regex or search regex. The more complicated regex extensions fill many web age articles. Here is an advanced regex dedicated site:

Regular-Expressions.info - Regex Tutorial, Examples and Reference - Regexp Patterns