diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..fc8c8de
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,16 @@
+name: CI
+run-name: continuous integration
+on: [push]
+jobs:
+  test:
+    strategy:
+      matrix:
+        os: [ubuntu-20.04, ubuntu-22.04, ubuntu-latest]
+        cc: [gcc, clang]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v3
+      - run: ./tests/test.sh
+        shell: bash
+        env:
+          CC: ${{ matrix.cc }}
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 35f979c..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,6 +0,0 @@
-language: c
-compiler:
-    - gcc
-    - clang
-    - gfortran
-script: (cd tests; ./test.sh)
diff --git a/c b/c
index 3980e21..3621cb9 100755
--- a/c
+++ b/c
@@ -34,7 +34,7 @@ cleanup() {
 
 # Handle --help, -h, and zero args
 [[ "$1" == "--help" || "$1" == "-h" ]] && { help_msg 1; exit 0; }
-[[ "$#" -lt 1 ]] && { help_msg 2; exit 1; }
+[[ "$#" -lt 1 ]] && { help_msg 2; exit 2; }
 
 # ensure our $CC and $CXX variables are set
 [[ -z "$CC" ]]  && CC=cc
@@ -155,9 +155,14 @@ binname="$tmproot/$id.bin"
 run() {
     trap cleanup SIGINT
 
-    shift
-    (exec -a "$fname" "$binname" "$@")
-    ret=$?
+    if [ -x "$binname" ]; then
+      shift
+      (exec -a "$fname" "$binname" "$@")
+      ret=$?
+    else
+      echo
+      ret=4
+    fi
 
     trap - SIGINT
     cleanup
diff --git a/tests/shell/test.sh b/tests/shell/test.sh
index 0c56460..c544df1 100644
--- a/tests/shell/test.sh
+++ b/tests/shell/test.sh
@@ -12,19 +12,19 @@ line=$(eval "C_CACHE_SIZE=-10 $c" 2>&1); ret=$?
 fline="$(echo "$line" | head -n1)"
 assert "\$C_CACHE_SIZE=-10"\
      "'$fline' =~ warning:\\ \\\$C_CACHE_SIZE\\ should\\ be\\ a\\ positive\\ integer.*"
-assert "return" "$ret -eq 1"
+assert "return" "$ret -eq 2"
 
 # cache=0
 line=$(eval "C_CACHE_SIZE=0 $c" 2>&1); ret=$?
 fline="$(echo "$line" | head -n1)"
 assert "\$C_CACHE_SIZE=0" "'$fline' =~ Usage:.*"
-assert "return" "$ret -eq 1"
+assert "return" "$ret -eq 2"
 
 # cache=10
 line=$(eval "C_CACHE_SIZE=10 $c" 2>&1); ret=$?
 fline="$(echo "$line" | head -n1)"
 assert "\$C_CACHE_SIZE=10" "'$fline' =~ Usage:.*"
-assert "return" "$ret -eq 1"
+assert "return" "$ret -eq 2"
 
 ## Shell - help flags
 header2 "Shell - help flags"
@@ -33,7 +33,7 @@ header2 "Shell - help flags"
 line=$(eval "$c" 2>&1); ret=$?
 fline="$(echo "$line" | head -n1)"
 assert "c" "'$fline' =~ Usage:.*"
-assert "return" "$ret -eq 1"
+assert "return" "$ret -eq 2"
 
 # gives usage with --help
 line=$(eval "$c --help" 2>&1); ret=$?
diff --git a/tests/test.sh b/tests/test.sh
index 3972959..3711835 100755
--- a/tests/test.sh
+++ b/tests/test.sh
@@ -6,6 +6,11 @@ cd "$(dirname "$BASH_SOURCE")"
 # Load helpers
 source "./test_helpers.sh"
 
+[ -n "$CC" ]  && "$CC"  --version
+[ -n "$CXX" ] && "$CXX" --version
+[ -n "$FC" ]  && "$FC"  --version
+$c --version
+
 # Run tests
 source ./argument_and_link_test/test.sh
 source ./complex_arguments/test.sh