modify a datastream on the fly

Question

I need to hijack and modify a datastream. The stream consists of fixed-width commands. Each command is a new line, and the documentation says that each command starts and ends

Answer 1

This should do it, its a one liner

perl -pe '/^STX\s\w+\s\d+#\s\w+,(\w+)\sETX$/;$len=length($1);s/$1/" " x $len/e'

I tested using.

echo "STX NAM 100# LASTNAME,FIRSTNAME ETX" | perl -pe '/^STX\s\w+\s\d+#\s\w+,(\w+)\sETX$/;$len=length($1);s/$1/" " x $len/e'

and it returns

STX NAM 100# LASTNAME,          ETX

To ensure the strings are the same length i tested.

echo "STX NAM 100# LASTNAME,FIRSTNAME ETX" | perl -pe '/^STX\s\w+\s\d+#\s\w+,(\w+)\sETX$/;$len=length($1);s/$1/" " x $len/e'| perl -pe 'print length($_);'

Gives 36.

echo "STX NAM 100# LASTNAME,FIRSTNAME ETX"|perl -pe 'print length($_);'

Gives 36.