I'm trying to grep through a lot of old PowerBASIC source files in search of a variable, but I'm having trouble getting grep to avoid matching references to the variable in the end-of-line comments.
For example:
ANGLE = 40 ' THIS IS A COMMENT ABOUT ANGLE'S VALUE
FOO = 3/ANGLE ' ANGLE CAN APPEAR ON RIGHT SIDE AS WELL
DELTA = 35 ' ANGLE AND DELTA AREN'T FRIENDS
Initially I was using:
# grep "\bANGLE\b.*'" SRC_FILE.BAS
But -- besides ignoring lines with no comments -- it also prints out lines of code which don't use ANGLE at all (such as the DELTA line). This is because those lines happen to also have a single apostrophe (') in their comments (i.e. AREN'T).
I thought of piping the output to remove the lines I don't want with:
# grep "\bANGLE\b" SRC_FILE.BAS | grep -v "'.*\bANGLE\b"
But unfortunately it also removes the lines of code I do want that just happen to have "ANGLE" in their comments.
How do I get grep to match the lines of actual code involving ANGLE and ignore those lines with only matches in the comments?
grep "^[^']*\bANGLE\b" SRC_FILE.BAS
This only matches lines where everything to the left of ANGLE does not include '. It will have a problem similar to jnylen's solution if there's an apostrophe in a string.