.iterm_shell_integration.sh

#!/bin/bash
# This is based on "preexec.bash" but is customized for iTerm2.

# Note: this module requires 2 bash features which you must not otherwise be
# using: the "DEBUG" trap, and the "PROMPT_COMMAND" variable.  preexec_install
# will override these and if you override one or the other this _will_ break.

# This is known to support bash3, as well as *mostly* support bash2.05b.  It
# has been tested with the default shells on MacOS X 10.4 "Tiger", Ubuntu 5.10
# "Breezy Badger", Ubuntu 6.06 "Dapper Drake", and Ubuntu 6.10 "Edgy Eft".


# Copy screen-run variables from the remote host, if they're available.

# Saved copy of your PS1. Changes to PS1 from here on are ignored as it is
# re-set from PROMPT_COMMAND.
orig_ps1="${PS1}"

# This variable describes whether we are currently in "interactive mode";
# i.e. whether this shell has just executed a prompt and is waiting for user
# input.  It documents whether the current command invoked by the trace hook is
# run interactively by the user; it's set immediately after the prompt hook,
# and unset as soon as the trace hook is run.
preexec_interactive_mode=""

# Default do-nothing implementation of preexec.
function preexec () {
    true
}

# Default do-nothing implementation of precmd.
function precmd () {
    true
}

# This function is installed as the PROMPT_COMMAND; it is invoked before each
# interactive prompt display.  It sets a variable to indicate that the prompt
# was just displayed, to allow the DEBUG trap, below, to know that the next
# command is likely interactive.
function preexec_invoke_cmd () {
    last_hist_ent="$(history 1)";
    precmd;
    # This is an iTerm2 addition to try to work around a problem in the
    # original preexec.bash.
    # When the PS1 has command substitutions, this gets invoked for each
    # substitution and each command that's run within the substitution, which
    # really adds up. It would be great if we could do something like this at
    # the end of this script:
    #   PS1="$(prompt_prefix)$PS1($prompt_suffix)"
    # and have prompt_prefix set a global variable that tells precmd not to
    # output anything and have prompt_suffix reset that variable.
    # Unfortunately, command substitutions run in subshells and can't
    # communicate to the outside world. 
    # Instead, we have this workaround. We save the original value of PS1 in
    # $orig_ps1. Then each time this funciton is run (it's called from
    # PROMPT_COMMAND just before the prompt is shown) it will change PS1 to a
    # string without any command substitutions by doing eval on orig_ps1. At
    # this point preexec_interactive_mode is still the empty string, so preexec
    # won't produce output for command substitutions.
    export PS1="\[$(prompt_prefix)\]$(eval "echo \"$orig_ps1\"")\[$(prompt_suffix)\]"
    preexec_interactive_mode="yes";
}

# This function is installed as the DEBUG trap.  It is invoked before each
# interactive prompt display.  Its purpose is to inspect the current
# environment to attempt to detect if the current command is being invoked
# interactively, and invoke 'preexec' if so.
function preexec_invoke_exec () {
    if [[ -n "$COMP_LINE" ]]
    then
        # We're in the middle of a completer.  This obviously can't be
        # an interactively issued command.
        return
    fi
    if [[ -z "$preexec_interactive_mode" ]]
    then
        # We're doing something related to displaying the prompt.  Let the
        # prompt set the title instead of me.
        return
    else
        # If we're in a subshell, then the prompt won't be re-displayed to put
        # us back into interactive mode, so let's not set the variable back.
        # In other words, if you have a subshell like
        #   (sleep 1; sleep 2)
        # You want to see the 'sleep 2' as a set_command_title as well.
        if [[ 0 -eq "$BASH_SUBSHELL" ]]
        then
            preexec_interactive_mode=""
        fi
    fi
    if [[ "preexec_invoke_cmd" == "$BASH_COMMAND" ]]
    then
        # Sadly, there's no cleaner way to detect two prompts being displayed
        # one after another.  This makes it important that PROMPT_COMMAND
        # remain set _exactly_ as below in preexec_install.  Let's switch back
        # out of interactive mode and not trace any of the commands run in
        # precmd.

        # Given their buggy interaction between BASH_COMMAND and debug traps,
        # versions of bash prior to 3.1 can't detect this at all.
        preexec_interactive_mode=""
        return
    fi

    # In more recent versions of bash, this could be set via the "BASH_COMMAND"
    # variable, but using history here is better in some ways: for example, "ps
    # auxf | less" will show up with both sides of the pipe if we use history,
    # but only as "ps auxf" if not.
    hist_ent="$(history 1)";
    local prev_hist_ent="${last_hist_ent}";
    last_hist_ent="${hist_ent}";
    if [[ "${prev_hist_ent}" != "${hist_ent}" ]]; then
        local this_command="$(echo "${hist_ent}" | sed -e "s/^[ ]*[0-9]*[ ]*//g")";
    else
        local this_command="";
    fi;

    # If none of the previous checks have earlied out of this function, then
    # the command is in fact interactive and we should invoke the user's
    # preexec hook with the running command as an argument.
    preexec "$this_command";
}

# Execute this to set up preexec and precmd execution.
function preexec_install () {

    # *BOTH* of these options need to be set for the DEBUG trap to be invoked
    # in ( ) subshells.  This smells like a bug in bash to me.  The null stackederr
    # redirections are to quiet errors on bash2.05 (i.e. OSX's default shell)
    # where the options can't be set, and it's impossible to inherit the trap
    # into subshells.

    set -o functrace > /dev/null 2>&1
    shopt -s extdebug > /dev/null 2>&1

    # Finally, install the actual traps.
    PROMPT_COMMAND="preexec_invoke_cmd";
    trap 'preexec_invoke_exec' DEBUG;
}

# -- begin iTerm2 customization

# Runs after interactively edited command but before execution
function preexec() {
  printf "\033]133;C\007"
}

function remotehost_and_currentdir() {
  printf "\033]1337;RemoteHost=%s@%s\007" "$USER" $(hostname -f)
  printf "\033]1337;CurrentDir=%s\007" "$PWD"
}

function prompt_prefix() {
  printf "\033]133;D;\$?\007"
  remotehost_and_currentdir
  printf "\033]133;A\007"
}

function prompt_suffix() {
  printf "\033]133;B\007"
}

preexec_install

# This is necessary so the first command line will have a hostname and current directory.
remotehost_and_currentdir