diff --git a/.travis.yml b/.travis.yml
index 1fff02e..8d6d30a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,7 +17,7 @@ addons:
     - shellcheck
 
 install:
-  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then 
+  - if [ "$TRAVIS_OS_NAME" = 'osx' ]; then
       brew update && brew install openssl;
       brew info openssl;
       ln -s /usr/local/opt/openssl/lib/libcrypto.1.0.0.dylib /usr/local/lib/;
@@ -35,17 +35,17 @@ install:
 script:
   - echo "TEST_LOCAL=$TEST_LOCAL"
   - echo "NGROK_TOKEN=$(echo "$NGROK_TOKEN" | wc -c)"
-  - which openssl && openssl version
-  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then curl -sSL $SHFMT_URL -o ~/shfmt ; fi
-  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then chmod +x ~/shfmt ; fi
-  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then ~/shfmt -l -w -i 2 . ; fi
-  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then git diff --exit-code && echo "shfmt OK" ; fi
-  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then shellcheck -V ; fi
-  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then shellcheck **/*.sh && echo "shellcheck OK" ; fi
+  - command -V openssl && openssl version
+  - if [ "$TRAVIS_OS_NAME" = "linux" ]; then curl -sSL $SHFMT_URL -o ~/shfmt ; fi
+  - if [ "$TRAVIS_OS_NAME" = "linux" ]; then chmod +x ~/shfmt ; fi
+  - if [ "$TRAVIS_OS_NAME" = "linux" ]; then ~/shfmt -l -w -i 2 . ; fi
+  - if [ "$TRAVIS_OS_NAME" = "linux" ]; then git diff --exit-code && echo "shfmt OK" ; fi
+  - if [ "$TRAVIS_OS_NAME" = "linux" ]; then shellcheck -V ; fi
+  - if [ "$TRAVIS_OS_NAME" = "linux" ]; then shellcheck **/*.sh && echo "shellcheck OK" ; fi
   - cd ..
   - git clone https://github.com/Neilpang/acmetest.git && cp -r acme.sh acmetest/ && cd acmetest
-  - if [[ "$TRAVIS_OS_NAME" == "linux" ]] && [[ "$NGROK_TOKEN" ]]; then sudo NGROK_TOKEN="$NGROK_TOKEN" ./letest.sh ; fi
-  - if [[ "$TRAVIS_OS_NAME" == "osx" ]] && [[ "$NGROK_TOKEN" ]]; then sudo NGROK_TOKEN="$NGROK_TOKEN" OPENSSL_BIN="$OPENSSL_BIN" ./letest.sh ; fi
+  - if [ "$TRAVIS_OS_NAME" = "linux" -a "$NGROK_TOKEN" ]; then sudo NGROK_TOKEN="$NGROK_TOKEN" ./letest.sh ; fi
+  - if [ "$TRAVIS_OS_NAME" = "osx" -a "$NGROK_TOKEN" ]; then sudo NGROK_TOKEN="$NGROK_TOKEN" OPENSSL_BIN="$OPENSSL_BIN" ./letest.sh ; fi
 
 
 matrix: