Re: file input output problem

against file which has hard link to another file

You actually only have one file on disk (uniquely identified by the device and inode values, see stat and lstat) with, in effect, two references to it in the directory table. You can have multiple hard links all pointing to the same file if you like. Any change to one will appear in all of them. However, deleting one of them will leave the others in place.

$ echo "hello world" > xxyyzz
$ ln xxyyzz aabbcc
$ ln xxyyzz ddeeff
$ ls -li aabbcc ddeeff xxyyzz 
     45063 -rw-r--r--   3 root     root          12 Aug  7 23:36 aabbc
+c
     45063 -rw-r--r--   3 root     root          12 Aug  7 23:36 ddeef
+f
     45063 -rw-r--r--   3 root     root          12 Aug  7 23:36 xxyyz
+z
$ cat aabbcc 
hello world
$ echo bye >> ddeeff 
$ cat xxyyzz 
hello world
bye
$ rm aabbcc
$ ls -li aabbcc ddeeff xxyyzz
aabbcc: No such file or directory
     45063 -rw-r--r--   2 root     root          16 Aug  7 23:38 ddeef
+f
     45063 -rw-r--r--   2 root     root          16 Aug  7 23:38 xxyyz
+z
$
[download]

I hope this helps you.

Cheers,

JohnGG

Comment on Re: file input output problem Download Code

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Re^2: file input output problem by convenientstore (Pilgrim) on Aug 07, 2007 at 23:26 UTC
so bascially, my only option is `./perl.file done.txt > done.temp` [download] and then `cat done.temp > done.txt` [download]	[reply] [d/l] [select]
Re^3: file input output problem by Argel (Prior) on Aug 07, 2007 at 23:50 UTC
If the file is relatively small you could just read all of it into memory and then overwrite the file after you have made your changes. `#!/usr/bin/perl use strict; use warnings; my @contents; my $file = 'done.txt'; open IN, '<', $file or die "Could not open $file for reading."; while (<IN>) { $_ =~ s/yahoo/never/g; push @contents, $_; } close IN or die "Could not close $file after reading."; open OUT, '>', $file or die "Could not open $file for writing."; foreach my $line ( @contents ) { print OUT $line or die "Failed to write to $file ($line)." } close OUT or die "Could not close $file after writing.";` [download]	[reply] [d/l]