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Bash assign string to variable

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# 1  
Old 02-02-2011
Bash assign string to variable
Hi ,I am trying to assign string to variable ,but it doesn't work
Also could you show me different ways to use grep,(I am trying to get the first,second and first column form file,and I am counting the chars)
Code:
let name=`grep "$id" product | cut -c6-20`

# 2  
Old 02-02-2011
What is it that you're trying to achieve here? Can you give an example?
You want to search something from the first 2 lines? And also the first column entirely?

You would be better off using awk and sed.
# 3  
Old 02-02-2011
I am extracting the second column in the file product ,and trying to assign this column which is string to variable name
Thanks
# 4  
Old 02-02-2011
Ok. So if an input file looks like this:

Code:
Column01 Column02 Column03
Column11 Column12 Column13
Column21 Column22 Column23

Then you have 2 ways of doing this:
1. Do it by reading the file line by line:


Code:
while read FILE_LINE
do
	MULTIPLE_COMMANDS=`echo $FILE_LINE | awk '{print $2}'`
	echo $MULTIPLE_COMMANDS
done < $INPUT_FILE

Output:
Column02
Column12
Column22

2. Do it by using just one command:

Code:
SINGLE_COMMAND=`cat $1 | awk '{print $2}'`
echo $SINGLE_COMMAND

Output:
Column02 Column12 Column22

# 5  
Old 02-02-2011
let is an arithmetic assignment in ksh. Just leave it out:
Code:
name=`grep "$id" product | cut -c6-20`

or
Code:
name=$(grep "$id" product | cut -c6-20)

# 6  
Old 02-02-2011
Thanks ,it works
How can I check if the product id exist with this line
`grep "$id" invertory | cut -c6-10`
what kind of return is going to have if it is eof and it didnt find it


Code:
#!/bin/bash
echo -n "Please provide a product id: "
read id
let qty=`grep "$id" invertory | cut -c6-10`
echo $qty
let price=`grep "$id" invertory | cut -c11-15`
let result=$qty\*$price
name=$(grep "$id" product | cut -c6-20)    
echo $name  total is $result

# 7  
Old 02-02-2011
Quote:
Originally Posted by Scrutinizer
let is an arithmetic assignment in ksh.
as well as bash. it's actually all right to use it.

---------- Post updated at 08:39 PM ---------- Previous update was at 08:35 PM ----------

Quote:
Originally Posted by lio123
Thanks ,it works
How can I check if the product id exist with this line
`grep "$id" invertory | cut -c6-10`
what kind of return is going to have if it is eof and it didnt find it
man test. you can find test options to check for null strings. Or you can try checking $?
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