Totally revamp the way we handle .bashrc.

Summary:
I have spent some time groveling through the bash manpages, and am
clearer now on the difference between .bashrc and .bash_profile --
basically, one is used for login shells and one for non-login shells.

We want our code to run in both contexts, so I have moved everything
to .bash_profile, which I now source from .bashrc.  (I actually only
source .bash_profile.khan, to keep any existing .bash_profile stuff
out of it, since maybe the user *does* want that stuff to be
login-only.)

I also separate out .bash_profile -- which is bash-specific -- from
.profile -- which runs on any sh-compatible shell, including zsh.
This should make it easier for zsh users to do their setup.

Test Plan:
I created a new user on my machine, and ran
   make
in the khan-dotfiles directory.  It created all the files the way they
should be.  I then ran
   bash
   git rb
and saw that the git alias was picked up; that is, the git command
didn't say 'rb not found'.  I then ran
   bash --login
   git rb
and saw that it was picked up as well (it wasn't, before this change).

Reviewers: marcos, alpert

Reviewed By: alpert

Subscribers: ayman

Differential Revision: http://phabricator.khanacademy.org/D13071

.bash_profile.khan

@@ -0,0 +1,39 @@
+################################################################################
+# Khan Academy specific .bash_profile
+#
+# The difference between .bash_profile and .profile is that the latter
+# is called for all sh-compatible shells.  So we put bashisms here
+# and non-bashisms in .profile.
+#
+# According to the bash manpage, if both .bash_profile and .profile
+# exist, bash only reads the first one.  So we have to source .profile
+# manually.
+
+if [ -s ~/.profile ]; then
+    source ~/.profile
+fi
+
+# Activate Python2.7 virtualenv
+source ~/.virtualenv/khan27/bin/activate
+
+# Figure out what directory we're *really* in (following symlinks).
+# We need this because *-completion.bash are siblings to this script.
+# http://stackoverflow.com/questions/59895/can-a-bash-script-tell-what-directory-its-stored-in
+SOURCE="${BASH_SOURCE[0]}"
+while [ -h "$SOURCE" ]; do   # follow symlinks
+  DIR="$( cd -P "$( dirname "$SOURCE" )" && pwd )"
+  SOURCE="$(readlink "$SOURCE")"
+  [[ $SOURCE != /* ]] && SOURCE="$DIR/$SOURCE"    # resolve relative symlink
+done
+DIR="$( cd -P "$( dirname "$SOURCE" )" && pwd )"
+
+# Enable autocompletion for git
+source "$DIR/git-completion.bash"
+
+# Make sure git (and other apps) prefer 'vim' to 'vi'.
+: ${EDITOR:=vim}
+
+# Set a high limit for open file descriptors per shell.
+# The default on OS X is 256; we increase it to 1024--the default value of
+# `sysctl kern.maxfilesperproc`, which `ulimit -n` must not exceed.
+ulimit -S -n 1024

.bashrc.khan

@@ -1,36 +1,14 @@
 ################################################################################
 # Khan Academy specific bashrc
-
-# Add Phabricator bins to PATH
-export PATH="$HOME/khan/devtools/arcanist/khan-bin:$PATH"
-
-# Add frankenserver bins to PATH
-export PATH="$HOME/khan/webapp/third_party/frankenserver:$PATH"
-
-# Add dotfiles scripts to PATH
-export PATH="$HOME/khan/devtools/khan-dotfiles/bin:$PATH"
-
-# Activate Python2.7 virtualenv
-source ~/.virtualenv/khan27/bin/activate
-
-# Figure out what directory we're *really* in (following symlinks).
-# We need this because *-completion.bash are siblings to this script.
-# http://stackoverflow.com/questions/59895/can-a-bash-script-tell-what-directory-its-stored-in
-SOURCE="${BASH_SOURCE[0]}"
-while [ -h "$SOURCE" ]; do   # follow symlinks
-  DIR="$( cd -P "$( dirname "$SOURCE" )" && pwd )"
-  SOURCE="$(readlink "$SOURCE")"
-  [[ $SOURCE != /* ]] && SOURCE="$DIR/$SOURCE"    # resolve relative symlink
-done
-DIR="$( cd -P "$( dirname "$SOURCE" )" && pwd )"
-
-# Enable autocompletion for git
-source "$DIR/git-completion.bash"
-
-# Make sure git (and other apps) prefer 'vim' to 'vi'.
-: ${EDITOR:=vim}
-
-# Set a high limit for open file descriptors per shell.
-# The default on OS X is 256; we increase it to 1024--the default value of
-# `sysctl kern.maxfilesperproc`, which `ulimit -n` must not exceed.
-ulimit -S -n 1024
+#
+# We actually store all our rc-code in .profile and .bash_profile.
+# The difference between .*profile and .bashrc is that the former
+# are loaded for login shells and the latter for non-login shells.
+# (For more info, see http://hacktux.com/bash/bashrc/bash_profile.)
+#
+# We want our code to run for both types of shells, so we just include
+# .bash_profile from here.  We source only .bash_profile.khan in case
+# you have code in your .bashrc_profile that you *don't* want executed
+# for non-login shells.
+
+source ~/.bash_profile.khan

.profile.khan

@@ -0,0 +1,51 @@
+################################################################################
+# Khan Academy specific .profile
+#
+# The difference between .bash_profile and .profile is that the latter
+# is called for all sh-compatible shells.  So we put non-bashisms here
+# and bashisms in .bash_profile.
+
+# Add Phabricator bins to PATH
+export PATH="$HOME/khan/devtools/arcanist/khan-bin:$PATH"
+
+# Add frankenserver bins to PATH
+export PATH="$HOME/khan/webapp/third_party/frankenserver:$PATH"
+
+# Add dotfiles scripts to PATH
+export PATH="$HOME/khan/devtools/khan-dotfiles/bin:$PATH"
+
+# Make sure git (and other apps) prefer 'vim' to 'vi'.
+: ${EDITOR:=vim}
+
+# Set a high limit for open file descriptors per shell.
+# The default on OS X is 256; we increase it to 1024--the default value of
+# `sysctl kern.maxfilesperproc`, which `ulimit -n` must not exceed.
+ulimit -S -n 1024
+
+
+# Mac-specific stuff.
+if [ `uname -s` = Darwin ]; then
+    # We need /usr/local/bin to come before /usr/bin on the path,
+    # to pick up brew files we install.
+    if ! echo "$PATH" | egrep -q '(:|^)/usr/local/bin/?:(.*:)?/usr/bin/?(:|$)'
+    then
+        # This replaces /usr/bin with /usr/local/bin:/usr/bin
+        PATH=`echo $PATH | sed -E 's,(^|:)(/usr/bin/?(:|$)),\1/usr/local/bin:\2,'`
+    fi
+
+    # Ideally we'd put /usr/local/sbin right before /usr/sbin, but
+    # there's so little in it we figure it's ok to put it first.
+    PATH=/usr/local/sbin:$PATH
+    export PATH
+
+    # Numpy/etc use flags clang doesn't know about.  This is only
+    # needed for mavericks.
+    if expr "`sw_vers -productVersion`" : 10.9 >/dev/null; then
+        CPPFLAGS="-Qunused-arguments $CPPFLAGS"
+        CFLAGS="-Qunused-arguments $CFLAGS"
+        # This ARCHFLAGS is needed until we have pyobjc 3.0, according to
+        #    https://bitbucket.org/ronaldoussoren/pyobjc/issue/66/cannot-locate-a-working-compiler-error
+        ARCHFLAGS="-Wno-error=unused-command-line-argument-hard-error-in-future $ARCHFLAGS"
+        export CPPFLAGS CFLAGS ARCHFLAGS
+    fi
+fi

bash_profile.default

@@ -0,0 +1,12 @@
+################################################################################
+# Local .bash_profile.
+# Feel free to add whatever you like after the 'bash_profile.khan' line.
+#
+# Note that .bash_profile.khan automatically sources ~/.profile if it
+# exists, so you don't have to worry that the addition of this file
+# "hides" .profile (bash won't load a .profile file if it sees a
+# .bash_profile file instead).
+
+if [ -s ~/.bash_profile.khan ]; then
+    source ~/.bash_profile.khan
+fi

mac-setup.sh

@@ -38,51 +38,14 @@ error () {
     printf "\r\033[2K  [\033[0;31mFAIL\033[0m] $1\n"
 }
 
-update_path() {
-    # We need /usr/local/bin to come before /usr/bin on the path,
-    # to pick up brew files we install.
-    if ! echo "$PATH" | egrep -q '(:|^)/usr/local/bin/?:(.*:)?/usr/bin/?(:|$)'
-    then
-        # This replaces /usr/bin with /usr/local/bin:/usr/bin
-        PATH=`echo $PATH | sed -E 's,(^|:)(/usr/bin/?(:|$)),\1/usr/local/bin:\2,'`
-        # Make this path update work in the future too.
-        path_update=`cat<<'EOF'
-echo $PATH | sed -E 's,(^|:)(/usr/bin/?(:|$)),\1/usr/local/bin:\2,'
-EOF`
-    else
-        path_update=''
-    fi
 
-    # Ideally we'd put /usr/local/sbin right before /usr/sbin, but
-    # there's so little in it we figure it's ok to put it first.
-    export PATH=/usr/local/sbin:$PATH
-
-    # Put these in shell config file too.
-    # Test whether it's already in a config file (sorry zsh users who
-    # aren't using .profile).  We follow the same order bash does:
-    if [ -f ~/.bash_profile ]; then
-        PROFILE_FILE="$HOME/.bash_profile"
-    elif [ -f ~/.bash_login ]; then
-        PROFILE_FILE="$HOME/.bash_login"
-    else
-        PROFILE_FILE="$HOME/.profile"
-    fi
-    if ! grep -q "export PATH=.*/usr/local/sbin" \
-        ~/.bash_profile ~/.bash_login ~/.profile; then
-        echo 'export PATH=/usr/local/sbin:$PATH' >> "$PROFILE_FILE"
-    fi
-    # Numpy/etc use flags clang doesn't know about.  This is only
-    # needed for mavericks.
-    if expr "`sw_vers -productVersion`" : 10.9 >/dev/null && \
-       ! grep -q -e "-Qunused-arguments" \
-        ~/.bash_profile ~/.bash_login ~/.profile; then
-        echo 'export CPPFLAGS="-Qunused-arguments $CPPFLAGS"' >> "$PROFILE_FILE"
-        echo 'export CFLAGS="-Qunused-arguments $CFLAGS"' >> "$PROFILE_FILE"
-    fi
-    if [ -n "$path_update" ]; then
-        echo "# Put /usr/local/bin right before /usr/bin" >> "$PROFILE_FILE"
-        echo 'PATH=`'"$path_update"'`' >> "$PROFILE_FILE"
-    fi
+update_path() {
+    # We need /usr/local/bin to come before /usr/bin on the path, to
+    # pick up brew files we install.  To do this, we just source
+    # .profile.khan, which does this for us (and the new user).
+    # (This assumes you're running mac-setup.sh from the khan-dotfiles
+    # directory.)
+    . .profile.khan
 }
 
 maybe_generate_ssh_keys () {

profile.default

@@ -0,0 +1,7 @@
+################################################################################
+# Local .profile.
+# Feel free to add whatever you like after the profile.khan' line.
+
+if [ -s ~/.profile.khan ]; then
+    . ~/.profile.khan
+fi

setup.sh

@@ -68,7 +68,7 @@ install_dotfiles() {
     # They all have the property they 'include' khan-specific code.
     for file in *.default; do
         dest="$ROOT/.`echo "$file" | sed s/.default$//`"  # foo.default -> .foo
-        ka_version=.`echo "$file" | sed s/default/khan/`  # .bashrc.khan
+        ka_version=.`echo "$file" | sed s/default/khan/`  # .bashrc.khan, etc.
         if [ ! -e "$dest" ]; then
             cp -f "$file" "$dest"
         elif ! fgrep -q "$ka_version" "$dest"; then