grep: fix "--quiet" overwriting current output
When grep is called with the --quiet option, the pager is initialized
despite not being used. When the pager is "less", anything output by
previous commands and not ended with a newline is overwritten:
$ echo -n aaa; echo bbb
aaabbb
$ echo -n aaa; git grep -q foo; echo bbb
bbb
This can be worked around, for example, by making sure STDOUT is not a
TTY or more directly by setting git's pager to "cat":
$ echo -n aaa; git grep -q foo > /dev/null; echo bbb
aaabbb
$ echo -n aaa; PAGER=cat git grep -q foo; echo bbb
aaabbb
But prevent calling the pager in the first place, which would also
save an unnecessary fork().
Signed-off-by: Wilhelm Schuermann <wimschuermann@googlemail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>