utmpdump: document optional filename argument

Signed-off-by: Bernhard Voelker <mail@bernhard-voelker.de>

diff --git a/login-utils/utmpdump.1 b/login-utils/utmpdump.1
index 65dfe329d2b5159b1f612ae55261888ed594ab3d..4df49dd99e519c4f32919840480571148c4a4fad 100644 (file)
--- a/login-utils/utmpdump.1
+++ b/login-utils/utmpdump.1
@@ -21,10 +21,13 @@ utmpdump \- dump UTMP and WTMP files in raw format
 .SH SYNOPSIS
 .B utmpdump
 .RB [ \-frh ]
-.I filename
+.I [ filename ]
 .SH DESCRIPTION
 \fButmpdump\fP is a simple program to dump UTMP and WTMP files
 in raw format, so they can be examined.
+\fButmpdump\fP reads from stdin unless a
+.I filename
+is passed.
 .SH OPTIONS
 .IP "\fB\-f, \-\-follow\fP"
 output appended data as the file grows.

diff --git a/login-utils/utmpdump.c b/login-utils/utmpdump.c
index ac072d4b4159c11659f118063300847caa483c36..fd3e74a32fb74ab55d7d3595960aa2bd7cda9457 100644 (file)
--- a/login-utils/utmpdump.c
+++ b/login-utils/utmpdump.c
@@ -190,7 +190,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
        fputs(USAGE_HEADER, out);
 
        fprintf(out,
-               _(" %s [options]\n"), program_invocation_short_name);
+               _(" %s [options] [filename]\n"), program_invocation_short_name);
 
        fputs(USAGE_OPTIONS, out);
        fputs(_(" -f, --follow           output appended data as the file grows\n"