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Old 03-04-2013, 08:17 AM   #1
gbao256
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I need a tutorial/explanation for this script


Hi, I'm learning some bash shell scripting and I found a code on the internet:

PHP Code:
find . -exec du -cbsh '{}' 
the "'{}' +" is very weird to me. I dont think i can google it because it is special character. Please help me

tks for all the reply below. I was understand it but I have some problem now:

Quote:
I dont want to create many topic because I'm a noob
I just want to get the total line so I wrote this code
Code:
find / -user u1 -type f -exec du -cbh '{}' + | tail -n 1
but it will search some thing in /proc folder and have some problem like that

Quote:
find: `/proc/2046/task/2046/fd/5': No such file or directory
find: `/proc/2046/task/2046/fdinfo/5': No such file or directory
find: `/proc/2046/fd/5': No such file or directory
find: `/proc/2046/fdinfo/5': No such file or directory
3132 total
how I can deny this. I just want to get the total line

Last edited by gbao256; 03-04-2013 at 11:21 AM.
 
Old 03-04-2013, 08:30 AM   #2
colucix
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It is part of the -exec syntax. It runs a single instance of the du command on the result of the search (multiple files). More details here: http://www.gnu.org/software/findutil...Multiple-Files
 
1 members found this post helpful.
Old 03-04-2013, 08:45 AM   #3
shivaa
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Once check this out here.

For understanding, you can devide this cmd in two parts, as:
Code:
find . -exec du -cbsh '{}' +
The part marked in red is searching for files inside current directory and keeps it in {}, which works like a container. Then in second part (marked in green) it executes some command on what first part has searched.

So it actually executes du -cbsh on files resulted from find . part.
Code:
du -cbsh file1
du -cbsh file2
du -cbsh file3 ... and so on

Last edited by shivaa; 03-04-2013 at 08:47 AM.
 
Old 03-04-2013, 08:52 AM   #4
druuna
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Quote:
Originally Posted by shivaa View Post
So it actually executes du -cbsh on files resulted from find . part.
Code:
du -cbsh file1
du -cbsh file2
du -cbsh file3 ... and so on
That is not correct!

This
Code:
find . -exec du -cbsh '{}' \;
results in
Code:
du -cbsh file1
du -cbsh file2
du -cbsh file3
And this
Code:
find . -exec du -cbsh '{}' +
results in
Code:
du -cbsh file1 file2 file3
 
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Old 03-04-2013, 09:45 AM   #5
gbao256
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tks for all your help it is very useful
 
Old 03-04-2013, 11:20 AM   #6
gbao256
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Posts: 10

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Sorry to tag it unsolved, but I have some problem with this code, I dont want to create many topic because I'm a noob
I just want to get the total line so I wrote this code
Code:
find / -user u1 -type f -exec du -cbh '{}' + | tail -n 1
but it will search some thing in /proc folder and have some problem like that

Quote:
find: `/proc/2046/task/2046/fd/5': No such file or directory
find: `/proc/2046/task/2046/fdinfo/5': No such file or directory
find: `/proc/2046/fd/5': No such file or directory
find: `/proc/2046/fdinfo/5': No such file or directory
3132 total
how I can deny this. I just want to get the total line
 
Old 03-04-2013, 11:34 AM   #7
shivaa
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These are pid file inside /proc corresponding to various process, which may have completed.

Also run this find command with root privileges, not a normal user, because you're seaching in root's home directory.

Code:
~$ su - root
~$ find / -user u1 -type f -exec du -cbh '{}' + | tail -n 1

OR

~$ sudo find / -user u1 -type f -exec du -cbh '{}' + | tail -n 1

Last edited by shivaa; 03-04-2013 at 12:15 PM. Reason: Typo
 
1 members found this post helpful.
Old 03-04-2013, 11:39 AM   #8
druuna
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@gbao256: Those message are generated by the find command.

Your find command also searches the /proc directory, which can be highly dynamic. The mentioned No such file or directory are files that have gone already.

To suppress them use this:
Code:
find / -user u1 -type f -exec du -cbh '{}' + 2>/dev/null | tail -n 1
You can also run into permission problems, see shivaa's post for a solution for that.
 
2 members found this post helpful.
Old 03-04-2013, 11:53 AM   #9
gbao256
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Quote:
Originally Posted by druuna View Post
@gbao256: Those message are generated by the find command.

Your find command also searches the /proc directory, which can be highly dynamic. The mentioned No such file or directory are files that have gone already.

To suppress them use this:
Code:
find / -user u1 -type f -exec du -cbh '{}' + 2>/dev/null | tail -n 1
You can also run into permission problems, see shivaa's post for a solution for that.
tks for u and shivaa reply.
Your code work. I was think about /dev/null but my code dont work
Code:
find / -user u1 -type f -exec du -cbh '{}' + >/dev/null | tail -n 1
can u tell me what is 2 is . I'm such a noob
ah, I remember something I was read is it output code ?
IS 1 is standard input 2 is standard output ?

Last edited by gbao256; 03-04-2013 at 11:56 AM.
 
Old 03-04-2013, 12:02 PM   #10
druuna
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1 (or "nothing") represents stdout en 2 stderr.

stdout outputs normal informations and stderr outputs errors.

Have a look here for the whole story: Standard streams

Bash related link: 3. All about redirection

Last edited by druuna; 03-04-2013 at 12:03 PM. Reason: added link
 
  


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