How to keep the field separator when printing $0 with awk

@Sukminder has already given the simple answer; I have a couple tidbits of style points and helpful syntax about your example code (like a code review). This started as a comment but it was getting long.

OFS is the output field separator, as already mentioned.

$0 is the default argument to print—no need to specify it explicitly. And another style point: awk has what's called "patterns", which are like built-in conditional blocks. So you could also just use:

awk -F'|' 'BEGIN {OFS = FS} NR != 1 {$5 += 0.1} {print}' myfile

You can set the Output Field Separator, OFS.

'BEGIN { OFS = "|" } ...'

Or:

'BEGIN { OFS = FS } ...'

It is <space> by default.