Create and document basic installation script

install.sh

@@ -0,0 +1,52 @@
+#!/bin/bash
+
+set -uo pipefail
+IFS=$'\n\t'
+
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+
+here=$(pwd)
+
+ret=0
+
+# If this use of readlink breaks, see
+# https://unix.stackexchange.com/questions/47710/find-only-destination-of-symlink
+# for discussion of alternatives.
+
+for i in _reformat-common.sh do-reformat.sh would-reformat.sh; do
+    if [[ -f "$here"/bin/"$i" ]] ; then
+        dest=$(readlink bin/$i)
+        if [[ x"$dest" == x"$DIR/$i" ]] ; then
+            echo $i is in place, good
+        else
+            echo $i exists but it is not a symlink or does not point to the right place
+            echo If it is a symlink, it points to: $dest
+            echo "(If it doesn't point anywhere, then it probably is not a symlink)"
+            ret=1
+        fi
+    else
+        # it doesn't exist; create it
+        echo setting $i up
+        mkdir -p $here/bin
+        ln -s $DIR/$i $here/bin/$i
+    fi
+done
+
+if [[ -f $here/.dir-locals.el ]] ; then
+    dest=$(readlink .dir-locals.el)
+    if [[ x"$dest" == x"$DIR/_dir-locals.el" ]] ; then
+        echo .dir-locals.el is in place, good
+    else
+        echo .dir-locals.el exists but it is not a symlink or does not point to
+        echo the right place
+        echo
+        echo It is possible that you are using .dir-locals.el for other purposes,
+        echo in which case this is not really an error.
+        ret=1
+    fi
+else
+    echo setting .dir-locals.el up
+    ln -s $DIR/_dir-locals.el $here/.dir-locals.el
+fi
+
+exit $ret