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writing a script

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writing a script

May 14th, 2004

I need to write the code for a script to count and display # of files and directories and then dispaly the # of each as well as the script name as output. I also have to sow a command to execut the script which I know already

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kc0arf

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Re: writing a script

May 14th, 2004

Hi,

Did you have any sample code to start with? What shell are you writing for? I sense that this is a homework problem... and while we like to help, we also encourage growth and self-learning.

Christian

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hotlantas69 hotlantas69 is offline

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Re: writing a script

May 14th, 2004

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Originally Posted by kc0arf

Hi,

Did you have any sample code to start with? What shell are you writing for? I sense that this is a homework problem... and while we like to help, we also encourage growth and self-learning.

Christian

Hi,
Wasn't sure what they meant by code. I have so far
ls | tee frizzle(script name) wc -l -d ./
Wasn't sure if I write that into a vi or do it drom the command prompt

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liliafan

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Re: writing a script

May 15th, 2004

The following script shows show I would do it, this is with a script instead of the commandline, of course in reality I would use perl but this is a basic idea on how to use bash to do it.

 Help with Code Tags 
 Shell Scripting Syntax (Toggle Plain Text) 
#!/bin/bash
 
directory=0
file=0
total=0
 
for a in `ls`
do
   if test -d $a; then
      directory=$(($directory+1))
   else
      file=$(($file+1))
   fi
 
   total=$(($total+1))
   echo $a
 
done
 
echo Total directories: $directory
echo Total files: $file
echo Total: $total
#!/bin/bash

directory=0
file=0
total=0

for a in `ls`
do
   if test -d $a; then
      directory=$(($directory+1))
   else
      file=$(($file+1))
   fi

   total=$(($total+1))
   echo $a

done

echo Total directories: $directory
echo Total files: $file
echo Total: $total

Of course if this is in fact a homework assignment the included code wouldn't get you a good grade it is intended just to show basically how it is done.

It can be pasted into a file and then run with: sh scriptname.sh

HTH

Ben

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Ludootje

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Re: writing a script

May 21st, 2004

IMHO you can keep it much simpler than liliafan's script, by using 'the right tool for the right job' as they say

 Help with Code Tags 
 Shell Scripting Syntax (Toggle Plain Text) 
#!/bin/bash
echo Total: $(ls | wc -l)
echo Total files: $(ls -F | grep -v /$ | wc -l)
echo Total dirs: $(ls -F | grep /$ | wc -l)
#!/bin/bash
echo Total: $(ls | wc -l)
echo Total files: $(ls -F | grep -v /$ | wc -l)
echo Total dirs: $(ls -F | grep /$ | wc -l)

(the '-F' option for ls adds symbols after certain types of files: a * after executables, a @ after symlinks, and a / after dirs)

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liliafan

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Re: writing a script

May 21st, 2004

You are right that would be a simpler method of doing it, but since it sounded a lot like a homework assignment I was hoping to just give an indication of how it could be done, whilst indicating that there was better ways to do it, rather than giving the answer in the simplest possible way :o)

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Ludootje

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Re: writing a script

May 22nd, 2004

Well by now I suppose (s)he had to hand in the assignment already (if it was homework in the first place), so now the only people benefitting (speeling?) from it would be other readers (or so I hope

).

Your script was very useful to me btw, didn't know you could do this in bash:

 Help with Code Tags 
 Shell Scripting Syntax (Toggle Plain Text) 
if test -d $a; then
if test -d $a; then

I thought you always needed

 Help with Code Tags 
 Shell Scripting Syntax (Toggle Plain Text) 
if [ -d $a ]; then
if [ -d $a ]; then

The math (i.e. the directory=$(($directory+1)) thing) is new to me too, I thought you always had to pipe those things thru 'bc'.

You got me curious with your remark about Perl though... how would this be done in Perl? Would it be easier than bash?
I suppose that'd be pretty much impossible, since bash was designed specifically for these things, but I'm not exactly a Perl expert

edit: added some code tags

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liliafan

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Re: writing a script

May 22nd, 2004

Ludootje - It can be done in perl very easily, and since primarily I am a perl programmer that would be my tool of choice.

 Help with Code Tags 
 Shell Scripting Syntax (Toggle Plain Text) 
opendir(TMP, "/adirectory");
while ($f=readdir(TMP)) {
   if (-d $f) {
      $directory++;
   } else {
      $file++;
   }
   $total++;
}
closedir(TMP);
opendir(TMP, "/adirectory");
while ($f=readdir(TMP)) {
   if (-d $f) {
      $directory++;
   } else {
      $file++;
   }
   $total++;
}
closedir(TMP);

Obviously just counting files this is a lot of work but in my experience if you are counting files and directories in real world situations you are going to do something with this output, which is where perl comes in handy.

In regards to the bash statements, I couldn't remember the syntax for "test"ing so I used the man pages and on the system I was on at the time (openBSD 3.2) that is the method described. The arithmatic functions in bash suck bad since if the syntax isn't 100% correct it will fail and often not even say that it has failed, I only used it because I was trying to use internal shell as much as possible and avoid external commands where I could. In terms of speed and real world usage for just counting your method is faster and more efficient.

Ben

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Ludootje

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Re: writing a script

May 22nd, 2004

Thanks *a lot* for posting that Perl example, Ben. I've been wondering for a while how hard system programming would be, and in Perl it seems fairly easy - I'm very much surprised that's all that's needed.
Easy to understand, too. I guess I should give Perl/Python another try...
Now if only it didn't take so long before being able to write something actually *useful*, I wouldn't give up so easily

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alc6379

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Re: writing a script

#10

May 22nd, 2004

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Originally Posted by Ludootje

I guess I should give Perl/Python another try...
Now if only it didn't take so long before being able to write something actually *useful*, I wouldn't give up so easily

I don't know about Perl, I'm assuming it'd be the same way, but with Python, it's SUPER easy, fun, in fact, to get up and going, and make useful programs with it. Python's syntax is such that you have to write decently clean looking code, as indentation is actually a way of dividing things up. This is unlike Perl, or even C, where you could just about omit white space to your heart's content, and make it look like a huge mess.

If you're interested, you should pick up the O'Reilly book, Learning Python. It's very short, and it gives you a good foundation that you can use and extend to checking out a book like Python Standard Library, which provides useful examples for programming with the various modules that come in the Python Distribution.

Alex Cavnar, aka alc6379