How to check if a string has spaces in Bash shell

Question

Say a string might be like "a b '' c '' d". How can I check that there is single/double quote and space contained in the string?

question from:https://stackoverflow.com/questions/1473981/how-to-check-if-a-string-has-spaces-in-bash-shell

Answer 1

You can use regular expressions in bash:

string="a b '' c '' d"
if [[ "$string" =~  |' ]]    #  slightly more readable: if [[ "$string" =~ ( |') ]]
then
   echo "Matches"
else
   echo "No matches"
fi

Edit:

For reasons obvious above, it's better to put the regex in a variable:

pattern=" |'"
if [[ $string =~ $pattern ]]

And quotes aren't necessary inside double square brackets. They can't be used on the right or the regex is changed to a literal string.