Default to stdin/stdout if no input files are
given to indent. FreeBSD and GNU indent have had
this behaviour for a long time now.
Based on FreeBSD svn rev 40502 from back in 1998.
Index: indent.1
===================================================================
RCS file: /cvs/src/usr.bin/indent/indent.1,v
retrieving revision 1.21
diff -u -p -r1.21 indent.1
--- indent.1 20 Jun 2013 06:28:15 -0000 1.21
+++ indent.1 20 Jun 2013 06:50:52 -0000
@@ -41,7 +41,7 @@
.Sh SYNOPSIS
.Nm indent
.Bk -words
-.Ar input-file Op Ar output-file
+.Op Ar input-file Op Ar output-file
.Op Fl bad | nbad
.Op Fl bap | nbap
.Op Fl bbb | nbbb
@@ -114,6 +114,11 @@ is specified,
.Nm
checks to make sure it is different from
.Ar input-file .
+.Pp
+If no
+.Ar input-file
+is specified
+input is read from stdin and the formatted file is written to stdout.
.Pp
The options listed below control the formatting style imposed by
.Nm .
Index: indent.c
===================================================================
RCS file: /cvs/src/usr.bin/indent/indent.c,v
retrieving revision 1.21
diff -u -p -r1.21 indent.c
--- indent.c 20 Jun 2013 06:28:15 -0000 1.21
+++ indent.c 20 Jun 2013 06:50:52 -0000
@@ -198,11 +198,10 @@ main(int argc, char **argv)
set_option(argv[i]);
} /* end of for */
if (input == NULL) {
- fprintf(stderr, "usage: indent input-file [output-file] [options]\n");
- exit(1);
+ input = stdin;
}
if (output == NULL) {
- if (troff)
+ if (troff || input == stdin)
output = stdout;
else {
out_name = in_name;
