add support for incremental timestamping

diff --git a/ts b/ts
index dd66e47bc098537e8b880d5898cf1230a6a83685..7e3fd064301d200bd897de6d668c5b2809c306c9 100755 (executable)
--- a/ts
+++ b/ts
@@ -6,7 +6,7 @@ ts - timestamp input
 
 =head1 SYNOPSIS
 
-ts [-r] [format]
+ts [-r] [-i] [format]
 
 =head1 DESCRIPTION
 
@@ -27,6 +27,11 @@ dates is not supported.
 If both -r and a format is passed, the existing timestamps are
 converted to the specified format.
 
+If the -i switch is passed, ts timestamps incrementally instead.  Every
+timestamp will be the time elapsed since the last timestamp.
+The default format changes to "%H:%M:%S", and "%.S" and "%.s" can be used
+as well.
+
 =head1 ENVIRONMENT
 
 The standard TZ environment variable controls what time zone dates
@@ -47,8 +52,9 @@ use POSIX q{strftime};
 $|=1;
 
 my $rel=0;
+my $inc=0;
 use Getopt::Long;
-GetOptions("r" => \$rel) || die "usage: ts [-r] [format]\n";
+GetOptions("r" => \$rel, "i" => \$inc) || die "usage: ts [-r] [-i] [format]\n";
 
 if ($rel) {
        eval q{
@@ -60,6 +66,9 @@ if ($rel) {
 
 my $use_format=@ARGV;
 my $format="%b %d %H:%M:%S";
+if ($inc) {
+       $format="%H:%M:%S";
+}
 $format=shift if @ARGV;
 
 # For subsecond resolution, Time::HiRes is needed.
@@ -69,17 +78,50 @@ if ($format=~/\%\.[Ss]/) {
        $hires=1;
 }
 
+my $lastseconds = 0;
+my $lastmicroseconds = 0;
+
+if ($hires) {
+       ($lastseconds, $lastmicroseconds) = Time::HiRes::gettimeofday();
+} else {
+       $lastseconds = time;
+}
+
+
 while (<>) {
        if (! $rel) {
                if ($hires) {
                        my $f=$format;
                        my ($seconds, $microseconds) = Time::HiRes::gettimeofday();
+                       if ($inc) {
+                               my $deltaseconds = $seconds - $lastseconds;
+                               my $deltamicroseconds = $microseconds - $lastmicroseconds;
+                               if ($deltamicroseconds < 0) {
+                                       $deltaseconds -= 1;
+                                       $deltamicroseconds += 1000000;
+                               }
+                               $lastseconds = $seconds;
+                               $lastmicroseconds = $microseconds;
+                               $seconds = $deltaseconds;
+                               $microseconds = $deltamicroseconds;
+                       }
                        my $s=sprintf("%06i", $microseconds);
                        $f=~s/\%\.([Ss])/%$1.$s/g;
-                       print strftime($f, localtime($seconds));
+                       if (!$inc) {
+                               print strftime($f, localtime($seconds));
+                       } else {
+                               print strftime($f, gmtime($seconds));
+                       }
                }
                else {
-                       print strftime($format, localtime);
+                       if ($inc) {
+                               my $seconds = time;
+                               my $deltaseconds = $seconds - $lastseconds;
+                               $lastseconds = $seconds;
+                               print strftime($format, gmtime($deltaseconds));
+                       } else {
+                               print strftime($format, localtime);
+                       }
                }
                print " ".$_;
        }