How to skip multiline comments delimited with /* */

Question

I'm trying to get the Bash script to read a text file and print out all the lines in it. I've successfully accomplished that by doing:

while read line; do
   $echo line
done < main.txt

However, I want it to ignore any lines in between /* and */. If I have a text file that looks like this:

hi
hru
/* 
look at my multiline comment function OoOoOoOh 
*/
good wbu
im fine

It will print out:

hi
hru
good wbu
im fine

are the `/*` and `*/` always on lines by themselves, or could they show up in lines intermixed with text you want to keep vs discard, eg, can something like `keep this text /* but ignore this text` and `ignore this text */ but keep this text` occur? please update the question with these additional details; also, what code have you tried to implement your filter requirements? — markp-fuso, Mar 17 '22 at 19:54
You could use `sed` to preprocess the file first, to strip out the comments. — Tim Roberts, Mar 17 '22 at 19:55
@markp-fuso They could show the way i did, or intermixed, yes — 1BL1ZZARD, Mar 17 '22 at 19:57
you should state that in the question as well as provide an example — markp-fuso, Mar 17 '22 at 20:07

score 0 · Accepted Answer · edited Mar 17 '22 at 20:03

0

If you don't need while loop, here is a one-liner:

$ sed -r ':a;$!{N;ba};s|/\*[^*]*\*+([^/*][^*]*\*+)*/\n||' main.txt
hi
hru
good wbu
im fine

If insisting on while:

while read line; do
  echo "$line"
done < <(sed -r ':a;$!{N;ba};s|/\*[^*]*\*+([^/*][^*]*\*+)*/\n||' main.txt)
hi
hru
good wbu
im fine

edited Mar 17 '22 at 20:03

John Kugelman

answered Mar 17 '22 at 20:01

Jarek

Sorry, forgot to add: sed taken from https://stackoverflow.com/questions/13061785/remove-multi-line-comments – Jarek Mar 17 '22 at 20:02
doesn't work if `/*` or `*/` show up in the middle of a line with both 'keep' and 'discard' text – markp-fuso Mar 17 '22 at 20:09

1 Answers1