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problem with read command


 
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# 1  
Old 08-06-2009
problem with read command

Hi Guys,

I am just trying to read data from a file.
The command i tried worked well with AIX server. But in SunOS, it is not reading.

Code:
cat log.out |sed -n '4,4p'| read value;
+ sed -n 4,4p
+ cat log.out
+ read value
echo $value;
+ echo

This is the log of running the script.

Can you people help me in figuring it out.. and also i want to know how the same command which worked on AIX is not working in SunOS.

Thanks & Regards,
Magesh
# 2  
Old 08-06-2009
I guess you are just going to get the 4th line.
The cat is not needed since sed can read files on it's own.

In bash you can do this
Code:
read VAR < <(sed '4!d' infile)
echo $VAR
test-9876

This should work in most shells and would also need no read:
Code:
VAR=`sed '4!d' infile`
echo $VAR

# 3  
Old 08-06-2009
zaxxon do we need to have two "<" in the code?
# 4  
Old 08-06-2009
We have Posix-standard and then we have real world Smilie - people who has done the shells.

Only in ksh you can use pipe:
Code:
cmd | read var1 var2 ...


Previous zaxxon example include howto read generic one variable:
Code:
var=$( cmd )

Previous zaxxon example include howto read more than one variable using bash.
Code:
read var1 var2 <  <(cmd)

Generic version for more than one variable read:
Code:
read var1 var2 <<EOF
$(cmd)
EOF


Last edited by kshji; 08-06-2009 at 05:33 AM..
# 5  
Old 08-06-2009
KShJi, i am using a ksh only..

But still why i am not able to pass the value to the read command ?

Can you please explain me?

Thanks in advance
# 6  
Old 08-06-2009
Code:
cat log.out | sed -n '4,4p'| read value
echo "$value"

Works fine with ksh88 and ksh93. Just tested - echo something, if log.out has more than 3 lines.
# 7  
Old 08-06-2009
this is the content of my file
Code:
tcmsd003:/usr/local/dsadm/dsprod/src>cat log.out

  COUNT(*)
----------
         1

Actually from the unix prompt if i run the same sed command, i am getting the desired output, in this case 1. But i have problem in the script only

---------- Post updated at 01:24 PM ---------- Previous update was at 01:23 PM ----------

This is the output of my sed command.
Code:
tcmsd003:/usr/local/dsadm/dsprod/src>sed -n '4,4p' log.out
         1


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