provide POSIX_FADV_SEQUENTIAL hint to appropriate utils

Following on from commit dae35bac, 01-03-2010,
"sort: inform the system about our input access pattern"
apply the same hint to all appropriate utils.
This currently gives around a 5% speedup for reading
large files from fast flash devices on GNU/Linux.

* src/base64.c: Call fadvise (..., FADVISE_SEQUENTIAL);
* src/cat.c: Likewise.
* src/cksum.c: Likewise.
* src/comm.c: Likewise.
* src/cut.c: Likewise.
* src/expand.c: Likewise.
* src/fmt.c: Likewise.
* src/fold.c: Likewise.
* src/join.c: Likewise.
* src/md5sum.c: Likewise.
* src/nl.c: Likewise.
* src/paste.c: Likewise.
* src/pr.c: Likewise.
* src/ptx.c: Likewise.
* src/shuf.c: Likewise.
* src/sum.c: Likewise.
* src/tee.c: Likewise.
* src/tr.c: Likewise.
* src/tsort.c: Likewise.
* src/unexpand.c: Likewise.
* src/uniq.c: Likewise.
* src/wc.c: Likewise, unless we don't actually read().

1 files changed, 5 insertions, 3 deletions

diff --git a/src/expand.c b/src/expand.c
index be50063b6..249255d15 100644
--- a/src/expand.c
+++ b/src/expand.c
@@ -40,6 +40,7 @@
 #include <sys/types.h>
 #include "system.h"
 #include "error.h"
+#include "fadvise.h"
 #include "quote.h"
 #include "xstrndup.h"
 
@@ -243,13 +244,14 @@ next_file (FILE *fp)
       if (STREQ (file, "-"))
         {
           have_read_stdin = true;
-          prev_file = file;
-          return stdin;
+          fp = stdin;
         }
-      fp = fopen (file, "r");
+      else
+        fp = fopen (file, "r");
       if (fp)
         {
           prev_file = file;
+          fadvise (fp, FADVISE_SEQUENTIAL);
           return fp;
         }
       error (0, errno, "%s", file);