Syntax error near =~ operator

问题

When I run this script:

#!/bin/bash

if [[ "abcd" =~ ^.*$ ]]; then
    echo "something"
fi

I get:

./tmp2.sh: line 3: conditional binary operator expected
./tmp2.sh: line 3: syntax error near `=~'
./tmp2.sh: line 3: `if [[ "abcd" =~ ^.*$ ]]; then'

I've tried all suggestions I've found, but still the same:/ Help me, please!

回答1:

Given that you're seeing a bash-specific error message, we can rule out that something other than bash is running the script (if it were a POSIX-features-only shell, such as sh on some systems, you'd instead see an error message relating to [[).

The most likely explanation:

• Your bash version is < 3.0, and therefore doesn't support the =~ operator.
  • To verify, run echo $BASH_VERSION in your script.

The specific error you're seeing is bash's way of saying: "I'm seeing a string I don't recognize as an operator."

回答2:

Run your script with bash script.sh not sh script.sh. It probably would also work with ./script.sh if script.sh is already executable since you're using the header #!/bin/bash.

回答3:

this should work

re='^.*$'
if [[ "abcd" =~ $re ]]; then
  echo "something"
fi

来源：https://stackoverflow.com/questions/24713891/syntax-error-near-operator