update on grep -l, its actually grep -I

so yeah i typed a lowercase L instead of an upper case i and yeah, that explains why some people werent able to parse source code correctly

give the grep manual a read; man grep in your terminal

the command i used for this text is: grep -I 'return' *c
which outputs to some extent:
xwidget.c: return NILP (ret) ? NULL : XXWIDGET_VIEW (ret);
xwidget.c: return xw;
xwidget.c: return xv->redisplayed;

again, this type of stuff is critical for analysis of invasive computer programs, more valid in the case of parsing source code

next update ill do is the basics of awk

unidef