diff --git a/Library/Homebrew/cmd/shellenv.sh b/Library/Homebrew/cmd/shellenv.sh
index 04d8121daf..257fec7e8e 100644
--- a/Library/Homebrew/cmd/shellenv.sh
+++ b/Library/Homebrew/cmd/shellenv.sh
@@ -6,8 +6,8 @@
 #:  Consider adding evaluation of this command's output to your dotfiles (e.g. `~/.profile`, `~/.bash_profile`, or `~/.zprofile`) with: `eval $(brew shellenv)`
 
 homebrew-shellenv() {
-  case "$SHELL" in
-    */fish|fish)
+  case "$(/bin/ps -p $PPID -o comm=)" in
+    fish|-fish)
       echo "set -gx HOMEBREW_PREFIX \"$HOMEBREW_PREFIX\";"
       echo "set -gx HOMEBREW_CELLAR \"$HOMEBREW_CELLAR\";"
       echo "set -gx HOMEBREW_REPOSITORY \"$HOMEBREW_REPOSITORY\";"
@@ -15,7 +15,7 @@ homebrew-shellenv() {
       echo "set -q MANPATH; or set MANPATH ''; set -gx MANPATH \"$HOMEBREW_PREFIX/share/man\" \$MANPATH;"
       echo "set -q INFOPATH; or set INFOPATH ''; set -gx INFOPATH \"$HOMEBREW_PREFIX/share/info\" \$INFOPATH;"
       ;;
-    */csh|csh|*/tcsh|tcsh)
+    csh|-csh|tcsh|-tcsh)
       echo "setenv HOMEBREW_PREFIX $HOMEBREW_PREFIX;"
       echo "setenv HOMEBREW_CELLAR $HOMEBREW_CELLAR;"
       echo "setenv HOMEBREW_REPOSITORY $HOMEBREW_REPOSITORY;"