-# check hash table before searching path.
-shopt -s checkhash
-# don't check path for sourced files.
-shopt -u sourcepath
-# ignore duplicate lines.
-HISTCONTROL=ignoredups
-# append to the history file.
-shopt -s histappend
-# automatically update window size if needed.
-shopt -s checkwinsize
-
-##############
-
-# make history writes immediate to avoid losing history if bash is zapped.
-echo $PROMPT_COMMAND | grep -q history
-if [ $? -ne 0 ]; then
- # we only change the prompt command if we think it hasn't already been done.
- export PROMPT_COMMAND="history -a;$PROMPT_COMMAND"
-fi
+ # check hash table before searching path.
+ shopt -s checkhash
+ # don't check path for sourced files.
+ shopt -u sourcepath
+ # ignore duplicate lines.
+ HISTCONTROL=ignoredups
+ # append to the history file.
+ shopt -s histappend
+ # automatically update window size if needed.
+ shopt -s checkwinsize