fix for scala#22443

Author: philwalk

dist/libexec/common-shared

@@ -6,16 +6,21 @@
 # *  Credits: This script is based on the script generated by sbt-pack.
 # *--------------------------------------------------------------------------*/
 
-# save terminal settings
-saved_stty=$(stty -g 2>/dev/null)
-# clear on error so we don't later try to restore them
-if [[ ! $? ]]; then
-  saved_stty=""
+if [ -e /usr/bin/tty -a "`tty`" != "not a tty" -a ! -p /dev/stdin ]; then
+  isterminal=1
+  # save terminal settings
+  saved_stty=$(stty -g 2>/dev/null)
+  # clear on error so we don't later try to restore them
+  if [[ ! $? ]]; then
+    saved_stty=""
+  fi
+else
+  isterminal=0
 fi
 
 # restore stty settings (echo in particular)
 function restoreSttySettings() {
-  stty $saved_stty
+  [ $isterminal -eq 1 ] && stty $saved_stty
   saved_stty=""
 }
 
@@ -61,7 +66,7 @@ if [[ ${cygwin-} || ${mingw-} || ${msys-} ]]; then
   CYGPATHCMD=`which cygpath 2>/dev/null`
   case "$TERM" in
     rxvt* | xterm* | cygwin*)
-      stty -icanon min 1 -echo
+      [ $isterminal -eq 1 ] && stty -icanon min 1 -echo
       JAVA_OPTS="$JAVA_OPTS -Djline.terminal=unix"
     ;;
   esac