How to compare strings in Bash

Question

How do I compare a variable to a string (and do something if they match)?

Answer 1

The following script reads from a file named "testonthis" line by line and then compares each line with a simple string, a string with special characters and a regular expression. If it doesn't match, then the script will print the line, otherwise not.

Space in Bash is so much important. So the following will work:

[ "$LINE" != "table_name" ] 

But the following won't:

["$LINE" != "table_name"] 

So please use as is:

cat testonthis | while read LINE
do
if [ "$LINE" != "table_name" ] && [ "$LINE" != "--------------------------------" ] && [[ "$LINE" =~ [^[:space:]] ]] && [[ "$LINE" != SQL* ]]; then
echo $LINE
fi
done