Delete a column from a delimited file in linux

Question

I have a file in the following format:

col1|col2|col3|col4
a|b|c|d
e|f||h
i|j|k|l

I would like to delete col3 (with the delimiter \"|\") fr

Answer 1

Here's a possible sed solution:

sed -i.bak filename -e 's;\(^.*|.*|\).*|\(.*\);\1\2;'

This will work great for your example, and could be adjusted for other examples, but isn't really a general purpose solution.

Explanation:

-i.bak Edit the file in place, first making a backup called filename.bak.

\(^.*|.*|\) From the start of the line, match everything up to and including the second delimiter. The parenthesis group this match (group 1).

.*| Match everything up to and including the last delimiter.

\(.*\) Match the rest and group (group 2).

\1\2 Replace all of the previous matches with the text from group 1 and group 2.