.bashrc: add persistent history and fix PROMPT_COMMAND

.bashrc

@@ -18,6 +18,13 @@ alias ll="ls -AF1"
 alias lll="ls -AFlh"
 alias ff="find 2>/dev/null"
 
+# history
+HISTCONTROL="ignoreboth:erasedups"
+HISTFILESIZE="-1"
+HISTIGNORE="q"
+shopt -s histappend
+PROMPT_COMMAND=${PROMPT_COMMAND:+${PROMPT_COMMAND%;}; }"history -a; history -c; history -r;"
+
 # bash completion
 if ! shopt -oq posix; then
 	if [ -f /usr/share/bash-completion/bash_completion ]; then
@@ -42,4 +49,4 @@ osc7_cwd() {
     done
     printf '\e]7;file://%s%s\e\\' "${HOSTNAME}" "${encoded}"
 }
-PROMPT_COMMAND="osc7_cwd; $PROMPT_COMMAND"
+PROMPT_COMMAND=${PROMPT_COMMAND:+${PROMPT_COMMAND%;}; }osc7_cwd