topic Re: Shell Scripting in Operating System - HP-UX

Shell Scripting

Virumandi — Fri, 29 Sep 2006 06:07:10 GMT

Hi

Any body help me in solving the issue
there are lot of files with .txt extension inside my folder.I want to create a script such that all the files ending with .txt needs to convert into .xls

The shell may be bash or any .NO PROBLEM

Anybody Help me pls

Re: Shell Scripting

Yang Qin_1 — Fri, 29 Sep 2006 06:20:52 GMT

Hi,

I believe you want to rename those files instead of convert.
If all .txt files are in the same directory:

#!/usr/bin/ksh

for fn in *.txt
do
newfn=`echo $fn|sed 's/txt/xls/'`
mv $fn $newfn
done

exit

Regards,
Yang

Re: Shell Scripting

Doug O'Leary — Fri, 29 Sep 2006 08:32:12 GMT

That's funny!

I actually use this exact problem as one of my interview questions...

(correct answer, btw)

Doug

Re: Shell Scripting

Peter Nikitka — Sun, 01 Oct 2006 05:35:10 GMT

Hi,

I'm soory but I must say that Yangs solution is not correct:

Having a file named
fn=allmytxtbooks.txt
newfn=`echo $fn|sed 's/txt/xls/'`

will lead to
allmyxlsbooks.txt

I suggest plain shell builtins, so no extra process is needed:

for fn in *.txt
do
mv $fn ${fn%*.txt}.xls
done

Error checking is left to the reader as an exercise :-)

mfG Peter

Re: Shell Scripting

Sandman! — Sun, 01 Oct 2006 15:40:23 GMT

If you are in the folder where the *.txt files are...

# ls -1 *.txt | awk -F. '{system("mv "$0" "$1".xls")}'

Re: Shell Scripting

H.Merijn Brand (procura — Sun, 01 Oct 2006 16:16:04 GMT

Wrong answer at an interview :)

The correct answer would be a new question:

Only at the current level, or recursive from the current folder?
And is the .txt extension case sensitive or not?
And are the .txt file containing CSV data, and do they have to be converted to real xls, or is a name change enough?
And should the new axtension match the casing of the old extension, or should it be all upper or lower case?
Are empty file to be renamed too? (empty .txt is valid text, empty .xls is not valid M$ Excel)
What is the host system, and should the script be portable (rename commands on VMS, M$Win, and *nix are quite different)

Too many questions to make a correct answer to this question.

$ perl -MFile::Find -MFile::Copy -e'find(sub{-s&&m/\.txt$/i or return;($n=$_)=~s/txt$/xls/i;move$_,$n},".")'

Addresses all above problems in one line.
Analysis is left an excercise to the reader.

Enjoy, Have FUN! H.Merijn

Re: Shell Scripting

Hein van den Heuvel — Sun, 01 Oct 2006 16:21:47 GMT

dead horse, but still...

System forks a process.
Find for a handful files, slow for thousands.
Personally I prefer the perl rename buildin:

For example, with the shell finding the candidate files:

perl -e 'while ($f = shift @ARGV) { $_ = $f; s/.tmp$/.xxx/; rename $f,$_ }' *.tmp

Other example with perl's glob finding the files....

perl -e 'while (<*.tmp>) { $old = $_; s/.tmp$/.xxx/; rename $old,$_ }'

Cheers,
Hein.

Re: Shell Scripting

Doug O'Leary — Mon, 02 Oct 2006 14:39:12 GMT

Holy crap! Some of you, procura especially, read *way* too much into a question.

It's the correct answer and gets the information I'm looking for in the intervew - specifically, can the person do a loop and does he or she know that you can't simply mv *.txt *.xls...

I did catch the fact that it'd catch xls in the middle of the filename; my usual way to do this is to use ${f%.*} just to strip off the extension. I would expect an admin that's working this problem to know his data; meaning he'd know if there was an xls in the middle of a set of filenames...

Since it's one question out of many, I'm sure I'll get whether or not the guy has the requisite attention to detail as well...

As for the rest of the answers, yet another proof that there's always multiple ways to solve problems in UNIX... Personally, I'd think using perl for the problem as stated would be akin to killing a fly with a small thermonuclear device, but if it works, have at it...

Doug

Re: Shell Scripting

Doug O'Leary — Mon, 02 Oct 2006 14:53:05 GMT

Holy crap! Some of you, procura especially, read *way* too much into a question.

It's the correct answer and gets the information I'm looking for in the intervew - specifically, can the person do a loop and does he or she know that you can't simply mv *.txt *.xls...

I did catch the fact that it'd match xls in the middle of the filename; The better answer given is my usual way to do this; use ${f%.*} just to strip off the extension. It does, however, do what the OP requested... I would expect an admin that's working this problem to know his data; meaning he'd know if there was an xls in the middle of a set of filenames...

Since it's one question out of many, I'm sure I'll get whether or not the guy has the requisite attention to detail as well...

As for the rest of the answers, yet another proof that there's always multiple ways to solve problems in UNIX... Personally, I'd think using perl for the problem as stated would be akin to killing a fly with a small thermonuclear device, but if it works, have at it, although the awk solution is interesting... I never think to use awk that way..

Doug

Re: Shell Scripting

Doug O'Leary — Mon, 02 Oct 2006 14:55:32 GMT

Holy crap! Some of you, procura especially, read *way* too much into a question.

It's the correct answer and gets the information I'm looking for in the intervew - specifically, can the person do a loop and does he or she know that you can't simply mv *.txt *.xls...

I did catch the fact that it'd match xls in the middle of the filename; The better answer given is my usual way to do this; use ${f%.*} just to strip off the extension. It does, however, do what the OP requested... I would expect an admin that's working this problem to know his data; meaning he'd know if there was an xls in the middle of a set of filenames...

Since it's one question out of many, I'm sure I'll get whether or not the guy has the requisite attention to detail as well...

As for the rest of the answers, yet another proof that there's always multiple ways to solve problems in UNIX... Personally, I'd think using perl for the problem as stated would be akin to killing a fly with a small thermonuclear device, but if it works, have at it (although the awk solution is interesting).

Doug

Re: Shell Scripting

Doug O'Leary — Mon, 02 Oct 2006 15:06:12 GMT

sorry for the multiple responses... I seem to be having problems accessing itrc site...

Doug

Re: Shell Scripting

H.Merijn Brand (procura — Mon, 02 Oct 2006 16:04:27 GMT

Doug, no problem. It of course depends on which environment you work in.
My environment arises the *need* to be portable across OS's (HP-UX, AIX, Linux, Cygwin, Win32), and accross databases (Oracle, Unify, postgres, Mysql), so you learn to program in a very defensive style, and never use system calls if either modules or builtins are available that enable you to do the same in a portable way.

My job is to be alert to any of these hidden questions and problems in questions from customers. "Can you please do A for me?" And they mean "B", but we should have known, as they always do so :) (wink wink)

If I interview someone on unix knowledge, I most of the time do not expect a `real' answer. I expect either the questions I asked, or a question like "what does the company prefer? bash, awk, sed, perl, csh, python?"
As Hein said: It's a dead horse. There are a zillion options to `fix' it or deal with it. It's just the question of how to do it reliable and the way no new errors arise.

Happy hacking!

Enjoy, Have FUN! H.Merijn

Re: Shell Scripting

Virumandi — Thu, 05 Oct 2006 23:43:25 GMT

Thanks to all of you...
The query has been resolved a little Earlier..

But I didnt updated the Ticket.But however I found that it became one of the interesting topic for the people to Talk..

Good...

Regards
Suseendran .A