bashcompare

Bash wants unary operator

I am using the following code to test if a function exists but Bash gives the following diagnostic:
[: =: unary operator expected

The code is:

if [ $(type -t deactivate) != function ];

How should this be expressed in a shell script independent manner?

Solution

  • It is in general not possible to use the same syntax for csh and bash.

    As for the error in your script: it is probably caused by the fact the type -t deactivate does not produce output. Proper quoting will solve that issue:

    if [ "$(type -t deactivate)" != "function" ] ; then