Pipe symbol | in AWK field delimiter

Question

I have a file foo that has the following data:

A<|>B<|>C<|>D
1<|>2<|>3<|>4

I want to prope

Answer 1

The pipe is a special character in a regex, so you need to escape it with a backslash. But this backslash is also a special character for the string literal, so it needs to be escaped again. So you end up with the following:

awk -F '<\\|>' '{$1=$1}1'

awk 'BEGIN {FS="<\\|>"} {$1=$1}1' 

The reason for this syntax is explained quite well here: http://www.gnu.org/software/gawk/manual/gawk.html#Computed-Regexps. In short, the expression is parsed twice.