I can’t fully understand the syntax in two cases:
1 - if not statement. For example I need to exclude windows OS then I try:

before_script:
  - if [[ "$TRAVIS_OS_NAME" != "windows" ]]; then 
      <some code>
but this doesn’t work
2 - I need to add dir to PATH env var within and out of if statement:
before_script:
  - if [[ "$TRAVIS_COMPILER" == "gcc" ]]; then 
      export PATH=$PATH:$CMAKE_INSTALL_PREFIX/lib;    # this works
    export PATH=$PATH:$CMAKE_INSTALL_PREFIX/bin;   # this doesn't work
could someone explain this? I can see the documentation about logical operators but it seems that it doesn’t cover my use cases…
My travis configuration file
This is invalid YAML. A multiline command should be inserted as a YAML literal block: 
before_install:
  if [[ $TRAVIS_OS_NAME == "windows" ]]; then
    echo Installing Google Chrome Stable...
    choco install googlechrome --acceptlicense --yes --no-progress --ignore-checksums
Use https://config.travis-ci.com/explore to check whether your .travis.yml can be parsed and what it is parsed into.
              
Thank you! good to know
I still can’t understand what is the syntax of if not equal expression…
before_script:
  - if [[ "$TRAVIS_OS_NAME" NOT EQUAL "windows" ]]; then 
      <some code>