grep: document -m better

* doc/grep.in.1, doc/grep.texi: Document behavior of -m 0 and -m -1.
This documents longstanding behavior, and is consistent with
how git grep -m will likely behave.

2 files changed, 14 insertions, 0 deletions

diff --git a/doc/grep.in.1 b/doc/grep.in.1
index aba085ad..5ba90ee2 100644
--- a/doc/grep.in.1
+++ b/doc/grep.in.1
@@ -321,6 +321,16 @@ Scanning each input file stops upon first match.
 Stop reading a file after
 .I NUM
 matching lines.
+If
+.I NUM
+is zero,
+.B grep
+stops right away without reading input.
+A
+.I NUM
+of \-1 is treated as infinity and
+.B grep
+does not stop; this is the default.
 If the input is standard input from a regular file,
 and
 .I NUM
diff --git a/doc/grep.texi b/doc/grep.texi
index b9688c82..b073fa76 100644
--- a/doc/grep.texi
+++ b/doc/grep.texi
@@ -341,6 +341,10 @@ Scanning each input file stops upon first match.
 @opindex --max-count
 @cindex max-count
 Stop after the first @var{num} selected lines.
+If @var{num} is zero, @command{grep} stops right away without reading input.
+A @var{num} of @minus{}1 is treated as infinity and @command{grep}
+does not stop; this is the default.
+
 If the input is standard input from a regular file,
 and @var{num} selected lines are output,
 @command{grep} ensures that the standard input is positioned