Bash Quoting
Quoting tells Bash how to treat special characters. Inside double quotes "...", variables are expanded but spaces and wildcards are kept as they are.
Inside single quotes '...', nothing is expanded: the text is used exactly as written. Use double quotes around variables to be safe.
Double quotes and single quotes
greeting="Hello"
echo "$greeting, World"
Hello, World
echo '$greeting, World'
$greeting, WorldBraces mark where the name ends
Use ${name} when letters follow the variable:
echo "${greeting}s"
Hellos
