topic Re: Script help needed (easy one) in Operating System - Linux

Script help needed (easy one)

TheJuiceman — Thu, 21 Jul 2005 19:37:38 GMT

OK...brain fart happening here....
I want to take a list that is in a file and execute a chown on each entry so that the owner is the same....

OK...I didn't even understand that. Let me lay it out like this...

File 1 contains the following entries:
abc
def

I want to execute a chown on each in a way like this...

chown abc abc

Therefore making the owner the same as the name of the file.

However I have a very long list to do...I'm lazy....and scripting is not my strength. Any help is appreciated.

Re: Script help needed (easy one)

Steven E. Protter — Thu, 21 Jul 2005 19:49:01 GMT

while read -r filename
do
chown $filename:$filename $filename
done < filelist

Thats a simple shell that changes ownership and group.

SEP

Re: Script help needed (easy one)

Muthukumar_5 — Thu, 21 Jul 2005 22:14:20 GMT

Only abc is as user rgt. You have to use as,

while read line;
do
chown $line $line
done < filename

or

awk '{ print "chown "$0" "$0 }' filename | sh

hth.

Re: Script help needed (easy one)

TwoProc — Thu, 21 Jul 2005 22:21:50 GMT

cat filename.list | xargs -i chown {} {}

Re: Script help needed (easy one)

TwoProc — Thu, 21 Jul 2005 22:23:29 GMT

for i in `cat filename.list'
do
chown $i $i
done

Re: Script help needed (easy one)

Muthukumar_5 — Thu, 21 Jul 2005 22:49:58 GMT

You can do also as,

perl -pi -e 's/^(.*)/chown \$1 \$1/'

sh

hth.

Re: Script help needed (easy one)

Sandman! — Mon, 25 Jul 2005 11:48:16 GMT

Bob,

Here is a one-line awk construct that can be used for your script:

# awk '{system("chown "$1":"$1" "$1)}' File1

cheers!

Re: Script help needed (easy one)

Rodney Hills — Mon, 25 Jul 2005 14:46:08 GMT

"xargs" is very handy for this sort of thing.

cat filename | xargs -i: chmod : :

HTH

-- Rod Hills

Re: Script help needed (easy one)

Tom Schroll — Mon, 25 Jul 2005 14:47:19 GMT

In agreement with one of John's answers, my vote is to use xargs. It's simple, very very fast, portable, and is designed for this purpose.

cat filename.list | xargs -i chown {} {}

You may need to escape the brackets {} depending on what shell you are using.

Things to note:
xargs is one of those small and fast swords to keep at your side. It can do great things at fast speeds in a very small package.

Another example of xargs would be change permissions of files:

cat filelist | xargs chmod 777

Or in another example, use find to pipe directly to xargs and print the cksum of each file:

find . -print | xargs cksum

And of course can be used to destroy things:

find . -print | xargs rm -f

(hehehe, DO NOT ACTUALLY DO THAT unless you want to whack all files in a directory)

Read the man page for xargs for more info.

-- Tom