unshare: fix SYNOPSIS and usage()

The "program" is optional and $SHELL is executed by default.

Addresses: https://github.com/karelzak/util-linux/issues/389
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/sys-utils/unshare.1 b/sys-utils/unshare.1
index ed316781506c2057f5556dd33918ec84c79e83a8..7c7d144d175a255f65e9fd2bd50d719e476a2e80 100644 (file)
--- a/sys-utils/unshare.1
+++ b/sys-utils/unshare.1
@@ -4,11 +4,12 @@ unshare \- run program with some namespaces unshared from parent
 .SH SYNOPSIS
 .B unshare
 [options]
-.I program
-.RI [ arguments ]
+.RI [ program
+.RI [ arguments ]]
 .SH DESCRIPTION
 Unshares the indicated namespaces from the parent process and then executes
-the specified \fIprogram\fR.
+the specified \fIprogram\fR. If \fIprogram\fR is not given, then ``${SHELL}'' is
+run (default: /bin/sh).
 .PP
 The namespaces can optionally be made persistent by bind mounting
 /proc/\fIpid\fR/ns/\fItype\fR files to a filesystem path and entered with

diff --git a/sys-utils/unshare.c b/sys-utils/unshare.c
index edd9bbe694b961d0e28e843d0d20269aa67bb6ee..0d02b70b3c80006456c217c99f6c1ddc3bd06e76 100644 (file)
--- a/sys-utils/unshare.c
+++ b/sys-utils/unshare.c
@@ -243,7 +243,7 @@ static void usage(int status)
        FILE *out = status == EXIT_SUCCESS ? stdout : stderr;
 
        fputs(USAGE_HEADER, out);
-       fprintf(out, _(" %s [options] <program> [<argument>...]\n"),
+       fprintf(out, _(" %s [options] [<program> [<argument>...]]\n"),
                program_invocation_short_name);
 
        fputs(USAGE_SEPARATOR, out);