监视一组文件的更改并在更改时对其执行命令

问题描述

我想到的(命令行)界面是这样的:

The (command line) interface I have in mind is like so:

watching FILE+ do COMMAND [ARGS] (and COMMAND [ARGS])*

COMMAND 中出现的任何{}"被替换为更改的文件的名称.并注意do"和and"是关键字.

Where any occurrence of "{}" in COMMAND is replaced with the name of the file that changed. And note that "do" and "and" are keywords.

例如:

> watching foo.txt bar.txt do scp {} somewhere.com:. and echo moved {} to somewhere

或者:

> watching foo.c do gcc foo.c and ./a.out

不过，我并不喜欢那个界面.我会添加我的脚本作为答案，看看是否有人有更好的方法或改进方法.

I'm not wedded to that interface though. I'll add my script that does that as an answer and see if anyone has anything better or ways to improve it.

推荐答案

#!/usr/bin/perl
# Run some commands whenever any of a set of files changes (see USAGE below).
# Example:
# ./watching.pl foo.txt bar.txt do scp foo.txt remote.com:. and cat bar.txt
# To only do something to the file that changed, refer to it as {}.

$| = 1;  # autoflush

my $p = position("do", @ARGV); # position of 1st occurrence of "do" in @ARGV.
if (@ARGV < 3 || $p == -1 || !($p >= 1 && $p < $#ARGV)) {
  die "USAGE: watching FILE+ do COMMAND [ARGS] (and COMMAND [ARGS])*
";
}

my $cmdstr = join(' ', splice(@ARGV, $p+1));  # grab stuff after the "do"
my @cmds = split(/s+ands+/, $cmdstr);
pop(@ARGV);  # remove the "do" on the end.
my @targets = @ARGV;
print "Watching {", join(' ', @targets), "} do (", join('; ', @cmds), "):
";

# initialize the %last hash for last mod time of each file.
for my $t (@targets) {
  ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,
   $atime,$mtime,$ctime,$blksize,$blocks) = stat($t);
  $last{$t} = $mtime;
}

my $i = 1;
while(1) {
  if($i % (45*60) == 0) { print "."; }

  for my $t (@targets) {
    ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,
     $atime,$mtime,$ctime,$blksize,$blocks) = stat($t);

    if ($mtime != $last{$t}) {
      print "
CHANGE DETECTED TO $t
";
      for (@cmds) { my $tmp = $_; $tmp =~ s/{}/$t/g; system($tmp); }
      $last{$t} = $mtime;
    }
  }
  sleep(1);
  $i++;
}


# Call like so: position($element, @list).
sub position {
  my $x = shift;
  if(@_==0) { return -1; }
  if($x eq $_[0]) { return 0; }
  shift;
  my $p = position($x,@_);
  if($p==-1) { return -1; }
  return 1+$p;
}

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