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Full Discussion: Using awk to read a specific line and a specific field on that line.
Top Forums Shell Programming and Scripting Using awk to read a specific line and a specific field on that line. Post 302543390 by agama on Sunday 31st of July 2011 01:13:43 PM
Old 07-31-2011
Quote:
Originally Posted by Bungkai

Code:
sed -i "s/$searchName\ $2/$name\ $lname/g" database.txt

This works for me assuming that searchName == John, $2 == Wall. If you've invoked your script with just John on the command line, $2 will be null, then you'll end up with the results that you posted. The small script I wrote to test your code includes some error checking that might be beneficial in your case so I've posted it as an example.

Code:
#!/usr/bin/env ksh

if [[ $# != 4 ]]
then
   echo "error: missing parms. expected:  name lastname newname new-lastname"
   exit 1
fi
searchName=$1
# $2 is not assigned and used directly later 
name=$3
lname=$4

sed  "s/$searchName\ $2/$name\ $lname/g" test.data

I would recommend assigning $2 to a named variable; while it is fine the way it is, it makes your script easier to read if it were something like this:

Code:
sed  "s/$searchName\ $searchLastname/$name\ $lname/g" test.data

I also don't believe that you need to escape the spaces. This should work:
Code:
sed  "s/$searchName $2/$name $lname/g" test.data

and again makes the code easier to read.

---------- Post updated at 13:13 ---------- Previous update was at 13:10 ----------

Thought I would also note that I dropped the -i from my testing because the version of sed that I prefer does not implement it. It should work just fine if you prefer to use that option.
 

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LEARN ABOUT MOJAVE

line

line(1)                                                            User Commands                                                           line(1)

NAME

       line - read one line

SYNOPSIS

       line

DESCRIPTION

       The  line utility copies one line (up to and including a new-line) from the standard input and writes it on the standard output. It returns
       an exit status of 1 on EOF and always prints at least a new-line. It is often used within shell files to read from the user's terminal.

EXIT STATUS

       Exit status is:

       0        Successful completion

       >0       End-of-file on input.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE         |      ATTRIBUTE VALUE        |
       +-----------------------------+-----------------------------+
       |Availability                 |SUNWcsu                      |
       +-----------------------------+-----------------------------+

SEE ALSO

       sh(1), read(2), attributes(5)

SunOS 5.10                                                          1 Feb 1995                                                             line(1)
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