Unix installer: add support for command-line arguments

Command-line arguments replace interactive prompts, which is
better for scripting runs of the installer.

pkgs/distro-build-pkgs/distro-build-client/unix-installer/installer-header

@@ -1,4 +1,93 @@
 
+###############################################################################
+## Command-line flags
+
+show_help() {
+  echo "Command-line flags:"
+  echo "/ --unix-style : install as Unix-style"
+  echo "\ --in-place : install in-place (not Unix-style)"
+  echo "  --dest <path> : install to <path>"
+  echo "  --create-dir : create destination for Unix-style if it does not exist"
+  echo "  --create-links <dir> : create links in <dir> for in-place install"
+  echo "  -h, --help : show this help"
+}
+
+where=""
+unixstyle=""
+accept_dirs=""
+SYSDIR=""
+SYSDIR_set=""
+
+while test $# -gt 0 ; do
+ case "$1" in
+  -h | --help)
+    show_help
+    exit 0
+    ;;
+  --unix-style)
+    if test "$unixstyle" != "" ; then
+      echo "conflicting or redundant flag: --unix-style"
+      exit 1
+    fi
+    unixstyle="Y"
+    accept_dirs="Y"
+    shift
+    ;;
+  --in-place)
+    if test "$unixstyle" != "" ; then
+      echo "conflicting or redundant flag: --in-place"
+      exit 1
+    fi
+    unixstyle="N"
+    SYSDIR_set="Y"
+    shift
+    ;;
+  --dest)
+    shift
+    if test $# -lt 1 ; then
+      echo "missing path for --dest"
+      exit 1
+    fi
+    where="$1"
+    if test "$where" = "" ; then
+      echo "empty path for --dest"
+      exit 1
+    fi
+    shift
+    ;;
+  --create-dir)
+    if test "$create_dir" != "" ; then
+      echo "redundant flag: --create-dir"
+      exit 1
+    fi
+    create_dir="Y"
+    shift
+    ;;
+  --create-links)
+    if test "$SYSDIR" != "" ; then
+      echo "redundant flag: --create-links"
+      exit 1
+    fi
+    shift
+    if test $# -lt 1 ; then
+      echo "missing path for --create-links"
+      exit 1
+    fi
+    SYSDIR="$1"
+    SYSDIR_set="Y"
+    if test "$SYSDIR" = "" ; then
+      echo "empty path for --create-links"
+      exit 1
+    fi
+    shift
+    ;;
+  *)
+    echo "unrecognized command-line argument: $1"
+    exit 1
+  ;;
+ esac
+done
+
 ###############################################################################
 ## Utilities
 
@@ -91,6 +180,7 @@ echo ""
 ###############################################################################
 ## What kind of installation?
 
+if test "$unixstyle" = ""; then
   echo "Do you want a Unix-style distribution?"
   echo "  In this distribution mode files go into different directories according"
   echo "  to Unix conventions.  A \"racket-uninstall\" script will be generated"
@@ -116,11 +206,13 @@ while test "$unixstyle" = "x"; do
     esac
   done
   echo ""
+fi
 
 ###############################################################################
 ## Where do you want it?
 ## sets $where to the location: target path for wholedir, prefix for unixstyle
 
+if test "$where" = ""; then
   if test "$unixstyle" = "Y"; then
     echo "Where do you want to base your installation of $DISTNAME?"
     echo "  (If you've done such an installation in the past, either"
@@ -152,6 +244,7 @@ case "x$where" in
     x4 | x. | x./ ) where="`pwd`${TARGET1}" ;;
     * ) expand_path_var where ;;
   esac
+fi
 
 ###############################################################################
 ## Default system directories prefixed by $1, mimic configure behavior
@@ -242,6 +335,7 @@ wholedir_install() {
   unpack_installation "$where"
   rm_on_abort=""
 
+  if test "$SYSDIR_set" != "Y"; then
     echo ""
     echo "If you want to install new system links within the \"bin\", \"man\""
     echo "  and \"share/applications\" subdirectories of a common directory prefix"
@@ -250,6 +344,7 @@ wholedir_install() {
     echo "  but not files."
     echon "(default: skip links) > "
     read SYSDIR
+  fi
   if test "x$SYSDIR" = "x"; then :
   elif test ! -d "$SYSDIR"; then
     echo "\"$SYSDIR\" does not exist, skipping links."
@@ -312,8 +407,10 @@ unixstyle_install() {
     failwith "The entered base directory exists as a file: $where"
   elif test ! -d "$where"; then
     echo "Base directory does not exist: $where"
+    if test "$create_dir" != "Y"; then
       echon "  should I create it? (default: yes) "
       read R; case "$R" in [nN]* ) abort ;; esac
+    fi
     "$mkdir" -p "$where" || failwith "could not create directory: $where"
   elif test ! -w "$where"; then
     failwith "The entered base directory is not writable: $where"
@@ -324,6 +421,7 @@ unixstyle_install() {
   set_dirs "$where"
   # loop for possible changes
   done="N"; retry="N"
+  if test "$accept_dirs" = "Y" ; then done="Y"; fi
   while test ! "$done" = "Y" || test "x$err" = "xY" ; do
     err="N"
     if test "$retry" = "N"; then