in reply to Re^3: Deleting a file after it runs?
in thread Deleting a file after it runs?

I still don't think that's right, at least for my system, running Linux.  It might be somehow different because you're using a ramdisk, but when I run this program: 
#!/usr/bin/perl -w
                                                                      
+          
my $iam = $0;
my $lscmd = "ls -lt $iam";
my $dfcmd = "df --block-size=1 .";
                                                                      
+          
printf "Before remove\n"; system($lscmd); system($dfcmd);    sleep 1;
unlink $0;
printf " After remove\n"; system($lscmd); system($dfcmd);    sleep 1;
printf "Try ^Z to see for yourself (cmd:  $dfcmd) ...\n"; sleep 5;
printf "Now exiting the program\n";

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it clearly shows that the space is freed up *before* the program exits.  The free space goes from 44290686976 bytes to 44290691072 (a difference of 4096 bytes) and remains at that value until after the program completes.   
[liverpole@golux ~/perl]% chmod +x rmtest2
[liverpole@golux ~/perl]% ls -lt rmtest2
-rwxrwxr-x    1 liverpole  liverpole       352 Oct  7 12:25 rmtest2*
[liverpole@golux ~/perl]% rmtest2
Before remove
-rwxrwxr-x    1 liverpole  liverpole       352 Oct  7 12:25 rmtest2
Filesystem            1-blocks      Used Available Use% Mounted on
/dev/hda2            77584592896 29352763392 44290686976  40% /
 After remove
ls: rmtest2: No such file or directory
Filesystem            1-blocks      Used Available Use% Mounted on
/dev/hda2            77584592896 29352759296 44290691072  40% /
Try ^Z to see for yourself (cmd:  df --block-size=1 .) ...
 
Suspended
[liverpole@golux ~/perl]% ls -lt rmtest2
ls: rmtest2: No such file or directory
[liverpole@golux ~/perl]% df --block-size=1 .
Filesystem            1-blocks      Used Available Use% Mounted on
/dev/hda2            77584592896 29352759296 44290691072  40% /
[liverpole@golux ~/perl]% fg
rmtest2
Now exiting the program
[liverpole@golux ~/perl]% df --block-size=1 .
Filesystem            1-blocks      Used Available Use% Mounted on
/dev/hda2            77584592896 29352759296 44290691072  40% /

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Re^5: Deleting a file after it runs?
by Hue-Bond (Priest) on Oct 07, 2005 at 19:44 UTC

    I bet that's because perl opens the file, reads it, closes it and then runs the code.

    $ cat > hw.pl
#!/usr/bin/perl
print "Hello, World!\n";
sleep 5;
print "exiting...\n";
$ chmod 755 !$
chmod 755 hw.pl
$ strace -o abc -tt -ff -s 500 !$
strace -o abc -tt -ff -s 500 hw.pl
$ _

(stripped strace output)
21:33:16.679617 open("/home/hue/lang/perl/hw.pl", O_RDONLY|O_LARGEFILE
+) = 3
21:33:16.681557 read(3, "#!/usr/bin/perl\nprint \"Hello, World!\\n\";\
+nsleep 5;\nprint \"exiting...\\n\";\n", 4096) = 72
21:33:16.681985 read(3, "", 4096)       = 0
21:33:16.682080 close(3)                = 0
21:33:16.682336 write(1, "Hello, World!\n", 14) = 14
21:33:16.683833 nanosleep({5, 0}, {5, 0}) = 0
21:33:21.663964 write(1, "exiting...\n", 11) = 11

    [download]

    Doing an lsof -n|grep hw shows that no process (except hw.pl itself) has the file opened, so when one unlinks it, the operation performs immediatly.

    --
    David Serrano

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[d/l]

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