How about a direct install with bash, curl and github

* Use curl to retrieve the raw install script from github
 * Execute payload directly with bash -c without requiring file write
 * Detect bash execution (as apposed to terminal or script file execution) and assume that this is a direct install
 * On direct install
 * * purge ~/.bash_it if present
 * * git clone repo to ~/.bash_it
 * * continue installation as normal

install.sh

@@ -1,8 +1,13 @@
 #!/usr/bin/env bash
 # bash-it installer
-BASH_IT=$(cd ${0%/*} && echo ${PWD})
-cd "${OLDPWD}"
 cp "${HOME}/.bash_profile" "${HOME}/.bash_profile.bak"
+if [ "$0" == "bash" ]; then
+  BASH_IT="${HOME}/.bash_it"
+  [[ -d "${BASH_IT}" ]] && rm -rf "${BASH_IT}"
+  git clone http://github.com/revans/bash-it.git "${BASH_IT}"
+else
+  BASH_IT=$(cd ${0%/*} && echo ${PWD})
+fi
 
 [[ "${BASH_IT}" != "${HOME}/.bash_it" ]] && cp -Rf "${BASH_IT}" "${HOME}/.bash_it"