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9.8. Removing a Directory and Its Contents
9.8.1. Problem
You
want to remove a directory tree recursively without using
rm -r.
9.8.2. Solution
Use the
finddepth function from File::Find, shown in Example 9-3.
Example 9-3. rmtree1
#!/usr/bin/perl
# rmtree1 - remove whole directory trees like rm -r
use File::Find;
die "usage: $0 dir ..\n" unless @ARGV;
find {
bydepth => 1,
no_chdir => 1,
wanted => sub {
if (!-l && -d _) {
rmdir or warn "couldn't rmdir directory $_: $!";
} else {
unlink or warn "couldn't unlink file $_: $!";
}
}
} => @ARGV;
Or use
rmtree from File::Path, as shown in Example 9-4.
Example 9-4. rmtree2
#!/usr/bin/perl
# rmtree2 - remove whole directory trees like rm -r
use File::Path;
die "usage: $0 dir ..\n" unless @ARGV;
foreach $dir (@ARGV) {
rmtree($dir);
}
WARNING:
These programs remove an entire directory tree. Use with extreme
caution!
9.8.3. Discussion
The File::Find module supports an alternate interface in which
find's first argument is a hash reference
containing options and their settings. The bydepth
option is the same as calling finddepth instead of
find. This is guaranteed to visit all files
beneath a directory before the directory itself, just what we need to
remove a directory and its contents. The no_chdir
option stops find from descending into directories
during processing; under this option, $_ is the
same as $File::Find::name. Finally, the
wanted option takes a code reference, our old
wanted( ) function.
We use two different functions,
rmdir and unlink; both default
to $_ if no argument is provided. The
unlink function deletes only files, and
rmdir deletes only empty
directories. We need to use finddepth or the
bydepth option to make sure we've first removed
the directory's contents before we rmdir the
directory itself.We first check that the file isn't a symbolic link before determining
whether it's a directory, because -d returns true
for both a real directory and a symbolic link to a directory.
stat, lstat, and file test
operators like -d all use the syscall
stat(2), which returns the file meta-information
stored in the file's inode. These functions and operators cache that
information in the special underscore (_)
filehandle. This permits tests on the same file while avoiding
redundant syscalls that would return the same information, slowly.According to POSIX, if the directory is either the root directory
(the mount point for the filesystems or the result of a
chroot(2) syscall) or the current working
directory of any process, it is unspecified whether the
rmdir syscall succeeds, or whether it fails and
sets errno ($! in Perl) to EBUSY ("Device
busy"). Many systems tolerate the latter condition, but few
the former.
9.8.4. See Also
The unlink, rmdir,
lstat, and stat functions in
perlfunc(1) and in Chapter 29 of
Programming Perl; the documentation for the
standard File::Find module (also in Chapter 32 of
Programming Perl); your system's
rm(1) and stat(2) manpages;
the -X section of
perlfunc(1), and the "Named Unary and File Test
Operators" section of Chapter 3 of Programming
Perl
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| 9.7. Processing All Files in a Directory Recursively |  | 9.9. Renaming Files |
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