Question

I am parsing a file to get the selected string and build into a single line, however, I don’t know how to do it(as shown in //add…) in shell scripts

while read line
do
    tt=`echo $line | cut -d'|' -f2 | cut -d'"' -f1`
    //add a $total = add all tt parts into a big string seperate by ", "
done < tmp_file

echo $total >> outfile

thank you

Answer 1

You append in the shell using assignment and variable expansion:

total="${total}, ${tt}"

The curly braces ({}) aren’t necessary in this case but I find they help distinguish variables when they’re next to each other like this.

This will give you a leading “, “. You can work around it like this:

total="${total:+${total}, }${tt}"

The ${variable:+value} construct only expands to value if variable is set.