diff --git a/script/install.sh b/script/install.sh
index 5ac3e2aff..2cefafc51 100755
--- a/script/install.sh
+++ b/script/install.sh
@@ -75,6 +75,14 @@ shopt -s expand_aliases
 # alias echo to alway print \newlines
 alias echo='echo -e'
 
+# run a command or print the error
+run_or_error() {
+  eval "$1"
+  if [ $? -ne 0 ]; then
+    error "executing '$1' failed."
+  fi
+}
+
 # nicely output error messages and quit
 error() {
   echo "\n"
@@ -87,28 +95,28 @@ error() {
 
 # shell interactive or not
 interactive_check() {
-  case $- in
-    *i*) # interactive
-      # all is well, continue
-      ;;
-    *) # non-interactive
-      TMPFILE='mktemp'
-      curl -s -o "$TMPFILE" "$D_INSTALL_SCRIPT_URL"
-      chmod +x "$TMPFILE"
-      exec 0< /dev/tty
-      bash -i "$TMPFILE"
-      rm "$TMPFILE"
-      exit 0
-      ;;
-  esac
+  fd=0 #stdin
+  if [[ -t "$fd" || -p /dev/stdin ]]; then
+    # all is well
+    echo ""
+  else
+    # non-interactive
+    TMPFILE='mktemp'
+    curl -s -o "$TMPFILE" "$D_INSTALL_SCRIPT_URL"
+    chmod +x "$TMPFILE"
+    exec 0< /dev/tty
+    bash -i "$TMPFILE"
+    rm "$TMPFILE"
+    exit 0
+  fi
 }
 
 # check if all necessary binaries are available
 binaries_check() {
   for exe in $BINARIES; do
-    echo -n "checking for $exe... " 
+    echo -n "checking for $exe... "
     which "$exe"
-    if [ $? -gt 0 ]; then
+    if [ $? -ne 0 ]; then
       error "you are missing $exe";
     fi
   done
@@ -124,11 +132,14 @@ to install, manage and work with multiple ruby environments.
 For more details check out https://rvm.io//
 EOT
 rvm_check() {
-  echo "checking for rvm..."
+  echo -n "checking for rvm... "
   rvm >/dev/null 2>&1
-  if [ $? -gt 0 ]; then
+  if [ $? -eq 0 ]; then
+    echo "found"
+  else
+    echo "not found"
     echo "$RVM_MSG"
-    read -p "Press [Enter] to continue without RVM or abort this script and install RVM"
+    read -p "Press [Enter] to continue without RVM or abort this script and install RVM..."
   fi
   echo ""
 }
@@ -141,23 +152,23 @@ sane_environment_check() {
 
 # find or set up a working git environment
 git_stuff_check() {
-  echo "Where would you like to put the git clone?"
-  echo "(or, where is your existing git clone)?"
+  echo "Where would you like to put the git clone, or, where is your existing git clone?"
+  echo "(please use a full path, not '~' or '.')"
   read -e -p "-> " D_GIT_CLONE_PATH
   echo ""
 
   test -d "$D_GIT_CLONE_PATH" \
     && cd "$D_GIT_CLONE_PATH" \
     && git status # folder exists? go there. is a good git clone?
-  if [ $? -gt 0 ]; then
-    mkdir "$D_GIT_CLONE_PATH" # only if it doesn't exist
+  if [ $? -ne 0 ]; then
     # not a git repo, create it?
-    echo "the folder you specified does not contain a git repo"
+    echo "the folder you specified does not exist or doesn't contain a git repo"
     read -p "Press [Enter] to create it... "
-    git clone "$D_REMOTE_REPO_URL" "$D_GIT_CLONE_PATH"
+    run_or_error "mkdir -p -v \"$D_GIT_CLONE_PATH\""  # only if it doesn't exist
+    run_or_error "git clone \"$D_REMOTE_REPO_URL\" \"$D_GIT_CLONE_PATH\""
   else
-    git checkout master
-    git pull
+    run_or_error "git checkout master"
+    run_or_error "git pull"
   fi
   echo ""
 }
@@ -175,8 +186,8 @@ database_question() {
       PgSQL )
         D_DB="postgres"
         # replace default with postgres
-        sed -i'' -r 's/(<<: \*mysql)/#\1/g' $D_DB_CONFIG_FILE
-        sed -i'' -r 's/(#(<<: \*postgres))/\2/g' $D_DB_CONFIG_FILE
+        run_or_error "sed -i'' -r 's/(<<: \*mysql)/#\1/g' \"$D_DB_CONFIG_FILE\""
+        run_or_error "sed -i'' -r 's/(#(<<: \*postgres))/\2/g' \"$D_DB_CONFIG_FILE\""
         break
         ;;
     esac
@@ -189,16 +200,16 @@ database_credentials() {
   read -e -p "username: " D_DB_USER
   read -e -p "password: " D_DB_PASS
 
-  sed -i'' -r "s/(host:)[^\n]*/\1 $D_DB_HOST/g" $D_DB_CONFIG_FILE
-  sed -i'' -r "s/(username:)[^\n]*/\1 $D_DB_USER/g" $D_DB_CONFIG_FILE
-  sed -i'' -r "s/(password:)[^\n]*/\1 $D_DB_PASS/g" $D_DB_CONFIG_FILE
+  run_or_error "sed -i'' -r \"s/(host:)[^\n]*/\1 $D_DB_HOST/g\" \"$D_DB_CONFIG_FILE\""
+  run_or_error "sed -i'' -r \"s/(username:)[^\n]*/\1 $D_DB_USER/g\" \"$D_DB_CONFIG_FILE\""
+  run_or_error "sed -i'' -r \"s/(password:)[^\n]*/\1 $D_DB_PASS/g\" \"$D_DB_CONFIG_FILE\""
 }
 
 # setup database
 # (assume we are in the Diaspora directory)
 database_setup() {
   echo "Database setup"
-  cp config/database.yml.example config/database.yml
+  run_or_error "cp config/database.yml.example \"$D_DB_CONFIG_FILE\""
   database_question
   database_credentials
   echo ""
@@ -238,7 +249,7 @@ git_stuff_check
 
 
 # goto working directory
-cd "$D_GIT_CLONE_PATH"
+run_or_error "cd \"$D_GIT_CLONE_PATH\""
 
 
 # configure database setup
@@ -246,15 +257,16 @@ database_setup
 
 
 echo "copying application.yml.example to application.yml"
-cp config/application.yml.example config/application.yml
+run_or_error "cp config/application.yml.example config/application.yml"
 echo ""
 
 echo "bundling..."
-bundle install
+run_or_error "bundle install"
 echo ""
 
 echo "creating and migrating default database in config/database.yml. please wait..."
-rake db:create db:migrate --trace
+run_or_error "rake db:create db:migrate --trace"
+             # I think we could use 'rake db:setup' here...
 echo ""
 
 define GOODBYE_MSG <<'EOT'