Improve pxeflatten script to support combining multiple files

1 files changed, 36 insertions, 7 deletions

diff --git a/pxeflatten b/pxeflatten
index cb80218..78a5c84 100755
--- a/pxeflatten
+++ b/pxeflatten
@@ -6,17 +6,22 @@
 # must all be on a single line. There is no support even for line
 # continuation. This makes managing complex configurations a pain.
 #
-# To help with this situation, this script will take a milt-line file (or
+# To help with this situation, this script will take a milti-line file (or
 # stdin if none is specified) and write flattened, single line output into
 # stdout ignoring #-comments and blank lines while at it.
 #
 # If you have prepared your PXELINUX config file so that the 'append' clause
-# is the last line without a trailing newline (but with a trailing space),
+# is the last line without a trailing newline (and without a trailing space),
 # then you can do:
 #
 # pxeflatten pxeconfig >>pxelinux.cfg/default
 #
-usage="usage: $0 [<file>]"
+# Options:
+#
+# -n
+#   Don't write trailing newline (useful for appending multiple configs).
+#
+usage="usage: $0 [-n] [<file>]"
 
 owd="$(pwd)"
 trap "{ cd '$owd'; exit 1; }" ERR
@@ -25,16 +30,40 @@ set -o errtrace # Trap in functions.
 function info () { echo "$*" 1>&2; }
 function error () { info "$*"; exit 1; }
 
+nl=true
+
+while [ "$#" -gt 0 ]; do
+  case "$1" in
+    -n)
+      nl=
+      shift
+      ;;
+    -*)
+      error "unknown option: $1"
+      ;;
+    --)
+      shift
+      break
+      ;;
+    *)
+      break
+      ;;
+  esac
+done
+
 if [ -z "$1" ]; then
   input="-"
 else
   input="$1"
 fi
 
-s=
 l=
 while read l || [ -n "$l" ]; do
-  echo -n "$s$l"
-  s=" "
+  echo -n " $l"
 done < <(sed -e '/^\s*#/d;/^\s*$/d;s/\s\s*/ /g' "$input")
-echo # Final newline.
+
+# Final newline.
+#
+if [ "$nl" ]; then
+  echo
+fi