First versions of the binaries and source file.

sw

@@ -0,0 +1,42 @@
+#!/bin/sh
+# It just swaps two files
+'
+FILE1=$1
+FILE2=$2
+
+function helpFn()
+{
+  ERROR=$?
+  if [[ $ERROR -gt 0 ]];
+  then
+    echo "$BINSELF error ($ERROR): "
+    perl -E 'say $!=shift' $ERROR
+  fi
+  echo "Usage: $BINSELF <file1> <file2>"
+  echo Swap two files in a filesystem.
+	exit $ERROR
+}
+
+if [[ $@ == *"--help"* ]];
+then
+	helpFn
+fi
+
+# We set a trap here, together with 'set -e' above,
+# this makes sure we exit gracefully if we have an
+# error in one of the ls or mv calls.
+trap helpFn ERR
+
+# We want to swap two files
+# Easy, but let's be safe about it
+ls "$FILE1" >/dev/null
+ls "$FILE2" >/dev/null
+
+# Files should exist, now we move
+mv "$FILE1" "$FILE1.sw"
+mv "$FILE2" "$FILE2.sw"
+
+# We got our moved copies, now we simply rename
+mv "$FILE1.sw" "$FILE2"
+mv "$FILE2.sw" "$FILE1"
+