On Oct 11 21:27:54, j...@wxcvbn.org wrote:
> Jan Stary <h...@stare.cz> writes:
>
> > The diff below makes head(1) recognize `-'
> > as a name for the standard input,
> > as many other utilities do.
>
> Makes sense to me. The following points could be improved IMO:
Updated diff below.
> - using strcmp sounds cleaner than those char comparisons
OK
> - I don't think the man page bits are needed. Utilities that read from
> stdin are supposed to support `-'. I'm not sure whether the extra
> example is really helpful.
I have removed the example.
I think the one sentence about "-" should stay;
other utils which recognize "-" mention it.
> - should we avoid closing stdin (multiple times)?
fixed
OK?
Jan
Index: head.1
===================================================================
RCS file: /cvs/src/usr.bin/head/head.1,v
retrieving revision 1.23
diff -u -p -r1.23 head.1
--- head.1 25 Oct 2015 21:50:32 -0000 1.23
+++ head.1 11 Oct 2016 21:05:07 -0000
@@ -47,6 +47,9 @@ utility copies the first
lines of each specified
.Ar file
to the standard output.
+A name of
+.Sq -
+is recognized as standard input.
If no files are named,
.Nm
copies lines from the standard input.
Index: head.c
===================================================================
RCS file: /cvs/src/usr.bin/head/head.c,v
retrieving revision 1.21
diff -u -p -r1.21 head.c
--- head.c 20 Mar 2016 17:14:51 -0000 1.21
+++ head.c 11 Oct 2016 21:05:07 -0000
@@ -30,6 +30,7 @@
*/
#include <stdio.h>
+#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <limits.h>
@@ -93,7 +94,8 @@ main(int argc, char *argv[])
if (pledge("stdio", NULL) == -1)
err(1, "pledge");
} else {
- if ((fp = fopen(*argv, "r")) == NULL) {
+ fp = strcmp(*argv, "-") ? fopen(*argv, "r") : stdin;
+ if (fp == NULL) {
warn("%s", *argv++);
status = 1;
continue;
@@ -101,7 +103,8 @@ main(int argc, char *argv[])
if (argc > 1) {
if (!firsttime)
putchar('\n');
- printf("==> %s <==\n", *argv);
+ printf("==> %s <==\n",
+ fp == stdin ? "(stdin)" : *argv);
}
++argv;
}
@@ -109,7 +112,8 @@ main(int argc, char *argv[])
while ((ch = getc(fp)) != EOF)
if (putchar(ch) == '\n')
break;
- fclose(fp);
+ if (fp != stdin)
+ fclose(fp);
}
/*NOTREACHED*/
}
