diff --git a/.bash_logout b/.bash_logout
index 0ea1ecd..6c254ae 100644
--- a/.bash_logout
+++ b/.bash_logout
@@ -2,11 +2,11 @@
 
 # Clear the screen/console on logout.
 if (( $SHLVL == 10 )); then
-  if [ -x /usr/bin/clear_console ]; then
+  if [[ -x /usr/bin/clear_console ]]; then
     /usr/bin/clear_console -q
-  elif [ -x /usr/bin/clear ]; then
+  elif [[ -x /usr/bin/clear ]]; then
     /usr/bin/clear
-  elif [ -x /usr/bin/tput ]; then
+  elif [[ -x /usr/bin/tput ]]; then
     /usr/bin/tput clear
   else
     echo -ne "\E[2J"
diff --git a/.bash_profile b/.bash_profile
index 0f76a53..00ba2d4 100644
--- a/.bash_profile
+++ b/.bash_profile
@@ -1,5 +1,5 @@
 # Souce bash specific set up,
-[ -f ~/.bashrc ] && . ~/.bashrc
+[[ -f ~/.bashrc ]] && . ~/.bashrc
 
 # Environment.
 export EDITOR="nano"
@@ -11,17 +11,17 @@ export MANPAGER="less -Mis -PM'Page %dt$'"
 export PAGER="less"
 export PATH="/usr/local/sbin:/usr/sbin:/opt/sbin:/sbin:$PATH"
 export VISUAL="$EDITOR"
-[ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"
+[[ -x /usr/bin/lesspipe ]] && eval "$(SHELL=/bin/sh lesspipe)"
 
 # Platform specific set up.
 _PLATFORM="$(uname -s)"
-if [ "$_PLATFORM" = "Linux" ]; then
+if [[ "$_PLATFORM" = "Linux" ]]; then
   export I_WANT_A_BROKEN_PS=1
   export LYNX_CFG="$HOME/.lynx.cfg"
   export LYNX_LSS="$HOME/.lynx.lss"
-  export MANPATH="~/.local/share/man:$MANPATH"
+  export MANPATH="$HOME/.local/share/man:$MANPATH"
   hash dircolors >/dev/null 2>&1 && eval "$(dircolors -b ~/.dir_colors)"
-elif [ "$_PLATFORM" = "Darwin" ]; then
+elif [[ "$_PLATFORM" = "Darwin" ]]; then
   export LSCOLORS="ExGxdxdxCxDxDxbcacbeae"
   export MANPATH="/opt/local/share/man:$MANPATH"
   export PATH="/opt/local/sbin:/opt/local/bin:$PATH"
@@ -31,9 +31,9 @@ fi
 unset _PLATFORM
 
 # Add bin directories to PATH.
-[ -d "$HOME/files/bin" ] && export PATH="$HOME/files/bin:$PATH"
-[ -d "$HOME/.local/bin" ] && export PATH="$HOME/.local/bin:$PATH"
-[ -d "$HOME/bin" ] && export PATH="$HOME/bin:$PATH"
+[[ -d "$HOME/files/bin" ]] && export PATH="$HOME/files/bin:$PATH"
+[[ -d "$HOME/.local/bin" ]] && export PATH="$HOME/.local/bin:$PATH"
+[[ -d "$HOME/bin" ]] && export PATH="$HOME/bin:$PATH"
 
 # Make ssh-agent work better.
 hash ssh-add ssh-agent >/dev/null 2>&1 && {
@@ -95,13 +95,13 @@ hash ssh-add ssh-agent >/dev/null 2>&1 && {
 
 # Screen.
 hash screen >/dev/null 2>&1 && {
-  if [ ! -e ~/.hushlogin ]; then
-    if [ ! -z "$STY" ]; then
+  if [[ ! -e ~/.hushlogin ]]; then
+    if [[ ! -z "$STY" ]]; then
       echo "Screen $STY, window $WINDOW."
       echo
     else
       _SCREENS="$( screen -ls | grep '[[:alpha:]]' | egrep -v '^([[:digit:]]+|No) Socket(s)?' )"
-      if [ -n "$_SCREENS" ]; then
+      if [[ -n "$_SCREENS" ]]; then
         echo "$_SCREENS"
         echo
       else
@@ -114,9 +114,9 @@ hash screen >/dev/null 2>&1 && {
 }
 
 # Mail check.
-[ ! -z "$SSH_CONNECTION" ] && {
-  if [ -s /var/spool/mail/$USER ]; then
-    if [ -N /var/spool/mail/$USER ]; then
+[[ ! -z "$SSH_CONNECTION" ]] && {
+  if [[ -s /var/spool/mail/$USER ]]; then
+    if [[ -N /var/spool/mail/$USER ]]; then
       echo "You have new mail."
       echo
     else
diff --git a/.bashrc b/.bashrc
index 908000e..3e2aedc 100644
--- a/.bashrc
+++ b/.bashrc
@@ -155,7 +155,7 @@ PS4="+(\[\e[33m\]\\\$? = \$?\[$(tput sgr0)\]) \[$(tput bold)$(tput setaf 4)\]\${
 
 # Platform specific set up.
 _PLATFORM="$(uname -s)"
-if [ "$_PLATFORM" = "Linux" ]; then
+if [[ "$_PLATFORM" = "Linux" ]]; then
   # Linux specific aliases.
   hash ftpwho >/dev/null 2>&1 && alias ftpwho='ftpwho -v'
   hash iftop >/dev/null 2>&1 && alias iftop='TERM=vt100 iftop'
@@ -171,7 +171,7 @@ if [ "$_PLATFORM" = "Linux" ]; then
   psgrep() {
     ps -auwwx | egrep "(RSS|$1)"
   }
-elif [ "$_PLATFORM" = "Darwin" ]; then
+elif [[ "$_PLATFORM" = "Darwin" ]]; then
   # Darwin specific aliases.
   hash df >/dev/null 2>&1 && alias df='df -P'
   hash ls >/dev/null 2>&1 && alias ls='ls -bFG'