SZIGETVÁRI János wrote:
I tried to look for already closed bugs that looked similar, but I did not manage to find anything similar.
Thanks for the bug report. We have fixed several bugs with fgrep since grep 2.16 came out. For what it's worth, I could not reproduce the bug with grep 2.20 (RHEL 6.8) either. Since the bug does not appear to occur with recent grep versions, I'm inclined to close the bug report.