Manage your PATH with a nice, one-directory-per-line file, rather than a gargantuan blob of colon-delimited text.

dotpath.sh

# Read the contents of ~/.path into $PATH, if ~/.path exists. ~/.path should be a file
# consisting of one path on each line, such as:
#
#   ~$ cat ~/.path
#   # vim: ft=sh
#   ~/usr/bin
#   /opt/local/bin
#   ... etc ...
#
# Note that comments begin with a hash (#).
# 
# awk-fu courtesy of pickledspiders:
#   http://www.reddit.com/r/linux/comments/1f1kd8/manage_your_path_with_a_nice_onedirectoryperline/ca5ww5d
# awk line fix courtesy of cpitchford:
#   http://www.reddit.com/r/linux/comments/1f1kd8/manage_your_path_with_a_nice_onedirectoryperline/ca61un7
DOT_PATH_FILE=~/.path
if [ -e "$DOT_PATH_FILE" ]; then
    export PATH=$PATH:`awk '/^[^#]/{printf "%s",(++x!=1?":":"")$0}' $DOT_PATH_FILE`
fi

Probably better to change the first line to this:

DOT_PATH_FILE="${DOT_PATH_FILE:-$HOME/.path}"

So someone can override the loopup by setting DOT_PATH_FILE before calling the script.

This is a litte better for the rest:

if [[ -e "$DOT_PATH_FILE" ]]; then
    export PATH="$PATH:$(awk '/^[^#]/{printf "%s",(++x!=1?":":"")$0}' "$DOT_PATH_FILE")"
fi

And for what its worth, ~ isn't a valid character in ~/.path.