On Friday, October 3, 2003, at 04:09 PM, Dean Do wrote:
> # sort /etc/passwd > /etc/passwd-new > # mv /etc/passwd-new /etc/passwd
Any good reason not to use the above? :)
[dean] Thanks for your response, James. The thing is... I have an existing Perl script that I working on and the above UNIX shell commands won't work in the Perl script. Is there a way to make them work?
Yes. Try:
`sort ...`; `mv...`;
Generally, this is considered a poor solution, because it's not very portable. I'll leave you to decide how important that is in this case.
Well, what would be the steps?
1. open /etc/passwd/ 2. read all entries into memory 3. close /etc/passwd/ 4. sort entries 5. open new file 6. print all entries 7. close new file 8. rename new file
Can you walk down that list replacing it with Perl statements?
[dean] That's a lot more steps to accomplish a simple sort of a text file. I can replace those steps with Perl statements. Thanks again for your help.
Maybe, but it's really not hard to code up and it's much more flexible. You can also shorten it up a little, if it's a big concern:
open OLD, '/etc/passwd' or die "File error: $!\n"; my @entries = sort grep !/^#/, <OLD>; open NEW, '>/etc/new_passwd' or die "File error: $!\n"; print foreach @entries; close NEW; rename '/etc/new_passwd', '/etc/passwd';
Hope that helps.
James
