Skip to content
Archive of posts tagged text processing

Remove duplicates, but keeping only the last occurrence

Again on IRC, somebody asked how to remove duplicates from a file, but keeping only the last occurrence of each item. The classic awk idiom awk '!a[$0]++' prints only the first instance of every line. So if the input is, for example foo bar baz foo xxx yyy bar the "normal" output (ie using the […]

“In-place” editing of files

Temporary files don't bite, so just use them.

Print lines in reverse order

Some silly ways to print lines in reverse order

Joining files with awk

Join lines from files based on keys

Smart ranges in awk, part two

Another variation on the theme