Problem assigning output to variable when using backticks and reading from STDIN

From: bernd (bew_ba_at_gmx.net)
Date: 11/29/05

  • Next message: bernd: "Re: Foreground recall" 
    Date: 29 Nov 2005 10:02:57 -0800

    Hello folks,

    the following is intended to check whether the loaded crontab is
    identical to the file stored on hard disk:

    > ls
    crontab test1.txt test2.txt
    > crontab -l | diff crontab -
    13c13
    < 0,5,10,15,20,25,35,40,45,50,55 0,5-23 * * * $HOME/hellow.ksh 

    ---
> #0,5,10,15,20,25,35,40,45,50,55 0,5-23 * * * $HOME/hellow.ksh
So far, so good.
As soon as I try to capture the result in a variable using backticks
things turn out to be strange:
> diffs=`crontab -l | diff crontab -`
> echo $diffs
13c13 < 0,5,10,15,20,25,35,40,45,50,55 0,5-23 crontab test1.txt
test2.txt
crontab test1.txt test2.txt crontab test1.txt test2.txt
$HOME/hellow.ksh--- > #0,5,10,15,20,25,35,40,45,50,550,5-23 crontab
test1.txt test2.txt crontab test1.txt test2.txt crontab test1.txt
test2.txt $HOME/hellow.ksh
The variable $diff contains the output in one line, the content of the
current directory interspersed into this line. Does somebody know the
reason for this strange behaviour and a workaround ?
The last command line is intended to work in a shell script and I need
the return code of the diff, so I cannot do something like:
crontab -l | diff crontab - | while read line
do
 ...
Any help appreciated.
Cheers
Bernd
  • Next message: bernd: "Re: Foreground recall"