Added location, updated link to the access-os-x-keychain-from-terminal blog post and added some explanatory text.

vj.sh

#!/usr/bin/env bash

# Canonical location: https://gist.github.com/kljensen/4434992 

##########################################################
#
# This is a shell script for keeping a journal that is
#   * plaintext,
#   * time-stamped,
#   * encrypted, and
#   * edited with vim.
#
# I find it convenient because it
#   * pulls the encryption key from OSX's KeyChain;
#   * is easily launched from the shell; and,
#   * can be stored in Dropbox.
#
# This is inspired by
#   * Manuel Ebert's jrnl: https://github.com/maebert/jrnl, and
#   * Sam Beam's post: http://chirp.syxyz.net/2011/06/keep-it-safe-with-blowfish-in-vim-7-3/
#
# To run this you will need:
#   * bash,
#   * expect,
#   * vim 7.3+, and,
#   * an "internet password" KeyChain item with 'Where' set to "ftp://vim-journal"
#     see http://www.frommknecht.net/2010/02/access-os-x-keychain-from-terminal/
#     (it won't really be used on the internet but that is one of the styles of passwords
#      that KeyChain stores and that we will be looking for in the script below)
#
# All those dependencies are included by default in
# recent versions of OSX.
#
# License: BSD 2-Clause.  See bottom.
#
##########################################################


# Turn off shell echo
#
set +o verbose

# Path to your journal. I keep mine in Dropbox.
#
JOURNAL_PATH="$HOME/Dropbox/journal.txt"

# Set KeyChain Item Name.  This corresponds
# to a name of ftp://vim-journal
#
KEYCHAIN_ITEM="vim-journal"

# Get password from OSX Keychain
#
PW=`security 2>&1 >/dev/null find-internet-password -gs vim-journal | cut -d '"' -f 2`
if [[ "$PW" == *"could not be found"* || "$PW" == "password: " ]]
then
    echo "vj.sh problem: No encryption password for $KEYCHAIN_ITEM in your KeyChain";
    return
fi

# Get the date
#
DATE=`date`

# Run vim inside expect
#
# Vim is started as described here
# http://chirp.syxyz.net/2011/06/keep-it-safe-with-blowfish-in-vim-7-3/
#
# The output of 'interact' is captured and supressed so as not to echo
# the encryption password.
#
# I put some '##' signs before the date, which is Markdown format.
# You can, of course, do whatever.  The \u001b puts vim back in edit
# mode before turning over control to the user via "interact".
#
expect -c "
spawn -noecho vim -nx --cmd \"set viminfo=\\\"\\\"\" --cmd \"set cryptmethod=blowfish\" $JOURNAL_PATH
expect -re \".+\" {
    send \"$PW\r\"
    send \"$PW\r\"
    send \"Go\n\n## $DATE\n\n\u001b\"
    interact
}"

# Copyright (c) 2013, Kyle Jensen
# All rights reserved.

# Redistribution and use in source and binary forms, with or 
# without modification, are permitted provided that the 
# following conditions are met:

# Redistributions of source code must retain the above 
# copyright notice, this list of conditions and the following 
# disclaimer.
# Redistributions in binary form must reproduce the above 
# copyright notice, this list of conditions and the following 
# disclaimer in the documentation and/or other materials 
# provided with the distribution.
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 
# CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 
# GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 
# BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 
# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
# POSSIBILITY OF SUCH DAMAGE.