GNU-ize Mac OS X El Capitan

gnuize.sh

#!/bin/bash

# Install required packages from Homebrew
brew tap homebrew/dupes
brew install coreutils binutils diffutils ed findutils gawk gnu-indent gnu-sed \
  gnu-tar gnu-which gnutls grep gzip screen watch wdiff wget bash gdb gpatch \
  m4 make nano file-formula git less openssh python rsync svn unzip vim \
  --default-names --with-default-names --with-gettext --override-system-vi \
  --override-system-vim --custom-system-icons
brew cleanup

# Empty the .bash_path file that holds GNU paths
echo 'export PATH="/usr/local/sbin:$PATH"' > ~/.bash_path

# Build PATH variable script in ~/.bash_path
for i in /usr/local/Cellar/*/*/bin; do
  echo 'export PATH="'$i':$PATH"' >> ~/.bash_path
done
for i in /usr/local/Cellar/*/*/libexec/gnubin; do
  echo 'export PATH="'$i':$PATH"' >> ~/.bash_path
done
for i in /usr/local/Cellar/*/*/share/man; do
  echo 'export MANPATH="'$i':$MANPATH"' >> ~/.bash_path
done
for i in /usr/local/Cellar/*/*/libexec/gnuman; do
  echo 'export MANPATH="'$i':$MANPATH"' >> ~/.bash_path
done

# Check if .bash_path is being called from .bash_profile
PATCH=`grep "~/.bash_path" ~/.bash_profile`
if [ "$PATCH" == "" ]; then
  # Add Ubuntu-style PS1 to .bash_profile
  cat <<EOF > ~/.bash_profile
alias ll="ls -ahl --color=always"
export PS1="\[\033[1;32m\]\u@\h\[\033[0m\]:\[\033[1;34m\]\w\[\033[0m\]# "
EOF
  # Add .bash_path to .bash_profile
  echo "source ~/.bash_path" >> ~/.bash_profile
fi

I have some issues with this code:

1. you should be extra vigilant not to introduce empty entries in $PATH
2. idem for MANPATH, but here it's needed inside the for-loops
3. it is considered good practice to test for the existence of a file before sourcing it in .bash_profile
4. your test weather .bash_profile is already patched is at the same time too specific and too fuzzy:
   1. it would match a line containing "~/Xbash_path" -- the dot being a placeholder in regexp
   2. it would not match a line conatining "$HOME/.bash_path"
5. the variable storing the test-result if the .bash_profile is already patched is named counter-intuitively. "PATCHED" would be better.
6. then again, there is no need to store the result in a variable at all, since "grep -q" can be used as condition to the "if"-block
7. you could mention somewhere that your script rebuilds $HOME/.bash_profile from scratch without leaving a backup copy if it doesn't find the bash_path-line

HTH, just my 2 cents

It currently will override my bash profile:

cat <<EOF > ~/.bash_profile

Can you changed it to

cat <<EOF >> ~/.bash_profile

FYI, I import this to a repository in https://github.com/ickc/GNU-ize