Bash regex match not matching exactly-CodePudding

I have a list of lines of text that I am looping through, looking for a specific term provided as a variable.

Let's say in this case, I am looking for my_search_term = "Ubuntu 2018".

My input lines of text look like this:

"Ubuntu 20.04LTS"
"Ubuntu 2018"

... so I am looking for something that will skip over the first string but echo and exit when it matches the second string.

for line in "${list_of_text_lines}"
do
    STR=$line
    SUB=$my_search_term
    if [[ "$STR" =~ .*"$SUB".* ]]; then
        echo $line
        exit
    fi
done

... but instead of echoing "Ubuntu 2018", I get "Ubuntu 20.04LTS". Why?

I appreciate any assistance, and thank you in advance!

Edit 1: As per @Barmar's suggestion, I removed the quotations around my input field, like so:

for line in ${list_of_text_lines}
do
    echo ${line}
    STR=$line
    SUB=$my_search_term
    if [[ "$STR" =~ .*"$SUB".* ]]; then
        echo $line
        exit
    fi
done

But this loops through the entire text string without matching, and my echo statements output the following:

...
"Ubuntu
2018"
"Ubuntu
20.04LTS"
...

CodePudding user response：

Without storing command output you can process input and do matching like this:

search_term='Ubuntu 2018'

while IFS= read -r line; do
   if [[ $line =~ $search_term ]]; then
      echo "matched: $line"
      exit
   fi
done < <(VBoxManage list vms)

PS: Note that your search term is not a regular expression, it is just a fixed string. In that case you can avoid regex and do glob comparison as well like this:

while IFS= read -r line; do
   if [[ $line == $search_term ]]; then
      echo "matched: $line"
      exit
   fi
done < <(VBoxManage list vms)