sed substitute situation


 
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# 1  
sed substitute situation

I am having a problem executing a sed substitute in a file. I have tried alot of different things I found in previous posts, however non seem to work.
I want to substitute this in $FILE:
VALUE=33.4

In the script I have tried the following:
prev=$(awk -F"=" '{ print $2 }' $FILE )
new=$(echo "scale=1; $prev * 10" | bc )

sed 's/$prev/$new/g' $FILE > NEW_FILE
sed 's/"$prev"/"$new"/g' $FILE > NEW_FILE
sed "s/$prev/$new/g" $FILE > NEW_FILE
sed "s/"$prev"/"$new"/g" $FILE > NEW_FILE
sed s/"$prev"/"$new"/g $FILE > NEW_FILE
sed s/$prev/$new/g $FILE > NEW_FILE


In each one of these sed says s/ is garbled or it does not do the substitue. Can anyone see something I am missing? Thanks alot.

Last edited by newbreed1; 06-03-2005 at 11:03 AM..
# 2  
Quote:
Originally Posted by newbreed1
I am having a problem executing a sed substitute in a file. I have tried alot of different things I found in previous posts, however non seem to work.
I want to substitute this in $FILE:
VALUE=33.4 for VALUE=44.0

In the script I have tried the following:
prev=$(awk -F"=" '{ print $2 }' $FILE )
new=$(echo "scale=1; 3.4 * 10" | bc )

sed 's/$prev/$new/g' $FILE > NEW_FILE
sed 's/"$prev"/"$new"/g' $FILE > NEW_FILE
sed "s/$prev/$new/g" $FILE > NEW_FILE
sed "s/"$prev"/"$new"/g" $FILE > NEW_FILE
sed s/"$prev"/"$new"/g $FILE > NEW_FILE
sed s/$prev/$new/g $FILE > NEW_FILE


In each one of these sed says s/ is garbled or it does not do the substitue. Can anyone see something I am missing? Thanks alot.

#3 should've worked.
post a couple of sample lines from $FILE [the ones with $prev], pls!
# 3  
At glance, I would say that is probably because the awk statement you have in the beginning does not produce the output you think it does.

if the substitution you want is as straightforward as you say then why not just use

sed 's/VALUE=33.4/VALUE=44.0/g' $FILE > NEW_FILE
# 4  
I am getting right, then why the dozen no of lines

sed -e 's/Value=x/Value=y/g'
# 5  
I apologize about the mis-code. True the awk does not produce these specific values. The values will change so I wanted to pass them to the sed script as variables. $prev will be what ever is found from the awk command.

prev=33.0
new=34.0
# 6  
Ooops,

While I was writing somebody else gave the command. Smilie
# 7  
Quote:
Originally Posted by newbreed1
I apologize about the mis-code. True the awk does not produce these specific values. The values will change so I wanted to pass them to the sed script as variables. $prev will be what ever is found from the awk command.

prev=33.0
new=34.0
so is there a problem NOW?
 

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