diff --git a/bin/tmuxifier b/bin/tmuxifier
index 3568f97..ae1e14d 100755
--- a/bin/tmuxifier
+++ b/bin/tmuxifier
@@ -3,12 +3,13 @@ set -e
 [ -n "$TMUXIFIER_DEBUG" ] && set -x
 
 resolve_link() {
-  $(type -p greadlink readlink | head -1) $1
+  $(type -p greadlink readlink | head -1) "$1"
 }
 
 abs_dirname() {
-  local cwd="$(pwd)"
+  local cwd
   local path="$1"
+  cwd="$(pwd)"
 
   while [ -n "$path" ]; do
     cd "${path%/*}"
@@ -22,11 +23,12 @@ abs_dirname() {
 
 if [ -z "${TMUXIFIER}" ]; then
   # Set TMUXIFIER relative to the "tmuxifier" executable.
-  export TMUXIFIER="$(dirname "$(abs_dirname "$0")")"
+  TMUXIFIER="$(dirname "$(abs_dirname "$0")")"
 else
   # Strip any trailing slash (/) characters from TMUXIFIER variable.
-  export TMUXIFIER="${TMUXIFIER%/}"
+  TMUXIFIER="${TMUXIFIER%/}"
 fi
+export TMUXIFIER
 
 # Load tmuxifier environment variables.
 source "$TMUXIFIER/lib/env.sh"
@@ -38,29 +40,25 @@ export PATH="$TMUXIFIER/libexec:$PATH"
 export TMUXIFIER_MIN_TMUX_VERSION="1.6"
 if [ "$(tmuxifier-tmux-version "$TMUXIFIER_MIN_TMUX_VERSION")" == "<" ]; then
   echo -e "ERROR: Tmuxifier requires Tmux v${TMUXIFIER_MIN_TMUX_VERSION}" \
-       "or newer. You have v$(tmuxifier-tmux-version)." >&2
+    "or newer. You have v$(tmuxifier-tmux-version)." >&2
   exit 1
 fi
 
 # Parse given command
 command="$1"
 case "$command" in
-  "" | "-h" | "--help" )
+  "" | "-h" | "--help")
     echo -e "tmuxifier $(tmuxifier-version)\n$(tmuxifier-help)" >&2
     ;;
-
-  "-v" | "--version" )
+  "-v" | "--version")
     tmuxifier-version
     ;;
-
-  * )
+  *)
     ! command_path="$(tmuxifier-resolve-command-path "$command")"
-
     if [ -z "$command_path" ]; then
       echo "tmuxifier: no such command '$command'" >&2
       exit 1
     fi
-
     shift 1
     exec "$command_path" "$@"
     ;;
diff --git a/completion/tmuxifier.bash b/completion/tmuxifier.bash
index 6d26e40..e4b2354 100644
--- a/completion/tmuxifier.bash
+++ b/completion/tmuxifier.bash
@@ -3,11 +3,12 @@ _tmuxifier() {
   local word="${COMP_WORDS[COMP_CWORD]}"
 
   if [ "$COMP_CWORD" -eq 1 ]; then
-    COMPREPLY=( $(compgen -W "$(tmuxifier commands)" -- "$word") )
+    COMPREPLY=($(compgen -W "$(tmuxifier commands)" -- "$word"))
   else
     local command="${COMP_WORDS[1]}"
-    local completions="$(tmuxifier completions "$command")"
-    COMPREPLY=( $(compgen -W "$completions" -- "$word") )
+    local completions
+    completions="$(tmuxifier completions "$command")"
+    COMPREPLY=($(compgen -W "$completions" -- "$word"))
   fi
 }
 
diff --git a/lib/layout-helpers.sh b/lib/layout-helpers.sh
index 68f7ea5..16b6072 100644
--- a/lib/layout-helpers.sh
+++ b/lib/layout-helpers.sh
@@ -140,7 +140,7 @@ balance_windows_horizontal() {
 #
 synchronize_on() {
   tmuxifier-tmux set-window-option -t "$session:${1:-$window}" \
-                 synchronize-panes on
+    synchronize-panes on
 }
 
 # Turn off synchronize-panes in a window.
@@ -150,7 +150,7 @@ synchronize_on() {
 #
 synchronize_off() {
   tmuxifier-tmux set-window-option -t "$session:${1:-$window}" \
-                 synchronize-panes off
+    synchronize-panes off
 }
 
 # Send/paste keys to the currently active pane/window.
@@ -180,7 +180,9 @@ run_cmd() {
 #   - $1: Directory path to use for session root.
 #
 session_root() {
-  local dir="$(__expand_path $@)"
+  local dir
+  dir="$(__expand_path "$@")"
+
   if [ -d "$dir" ]; then
     session_root="$dir"
   fi
@@ -192,7 +194,9 @@ session_root() {
 #   - $1: Directory path to use for window root.
 #
 window_root() {
-  local dir="$(__expand_path $@)"
+  local dir
+  dir="$(__expand_path "$@")"
+
   if [ -d "$dir" ]; then
     window_root="$dir"
   fi
@@ -214,9 +218,11 @@ load_window() {
     if [ $# -gt 1 ]; then
       window="$2"
     else
-      window="${1/%.window.sh}"
-      window="${window/%.sh}"
+      window="${1/%.window.sh/}"
+      window="${window/%.sh/}"
     fi
+
+    # shellcheck disable=SC1090
     source "$file"
     window=
 
@@ -258,11 +264,12 @@ load_session() {
   if [ $# -gt 1 ]; then
     session="$2"
   else
-    session="${1/%.session.sh}"
-    session="${session/%.sh}"
+    session="${1/%.session.sh/}"
+    session="${session/%.sh/}"
   fi
 
   set_default_path=true
+  # shellcheck disable=SC1090
   source "$file"
   session=
 
@@ -304,11 +311,11 @@ initialize_session() {
 
     # Set default-path for session
     if [ -n "$session_root" ] && [ -d "$session_root" ]; then
-      cd "$session_root"
+      cd "$session_root" || return 1
 
       $set_default_path && tmuxifier-tmux \
         set-option -t "$session:" \
-        default-path "$session_root" 1>/dev/null
+        default-path "$session_root" 1> /dev/null
     fi
 
   # Tmux 1.9 and later.
@@ -329,7 +336,8 @@ initialize_session() {
   # In order to ensure only specified windows are created, we move the
   # default window to position 999, and later remove it with the
   # `finalize_and_go_to_session` function.
-  local first_window_index=$(__get_first_window_index)
+  local first_window_index
+  first_window_index="$(__get_first_window_index)"
   tmuxifier-tmux move-window \
     -s "$session:$first_window_index" -t "$session:999"
 }
@@ -344,13 +352,12 @@ initialize_session() {
 # created, but already existed, then we'll need to specifically switch to it.
 #
 finalize_and_go_to_session() {
-  ! tmuxifier-tmux kill-window -t "$session:999" 2>/dev/null
+  ! tmuxifier-tmux kill-window -t "$session:999" 2> /dev/null
   if [[ "$(tmuxifier-current-session)" != "$session" ]]; then
     __go_to_session
   fi
 }
 
-
 #
 # Internal functions
 #
@@ -369,8 +376,11 @@ __expand_path() {
 }
 
 __get_first_window_index() {
-  local index=$(tmuxifier-tmux list-windows -t "$session:" \
-    -F "#{window_index}" 2>/dev/null)
+  local index
+  index="$(
+    tmuxifier-tmux list-windows \
+      -t "$session:" -F "#{window_index}" 2> /dev/null
+  )"
 
   if [ -n "$index" ]; then
     echo "$index" | head -1
@@ -380,16 +390,20 @@ __get_first_window_index() {
 }
 
 __get_current_window_index() {
-  local lookup=$(tmuxifier-tmux list-windows -t "$session:" \
-    -F "#{window_active}:#{window_index}" 2>/dev/null | grep "^1:")
+  local lookup
+  lookup="$(
+    tmuxifier-tmux list-windows -t "$session:" \
+      -F "#{window_active}:#{window_index}" 2> /dev/null | grep "^1:"
+  )"
 
   if [ -n "$lookup" ]; then
-    echo "${lookup/1:}"
+    echo "${lookup/1:/}"
   fi
 }
 
 __go_to_session() {
   if [ -z "$TMUX" ]; then
+    # shellcheck disable=2086
     tmuxifier-tmux $TMUXIFIER_TMUX_ITERM_ATTACH -u \
       attach-session -t "$session:"
   else
diff --git a/lib/util.sh b/lib/util.sh
index eeaf9a2..02e4a2e 100644
--- a/lib/util.sh
+++ b/lib/util.sh
@@ -1,11 +1,11 @@
 calling-help() {
-  if [[ " $@ " != *" --help "* ]] && [[ " $@ " != *" -h "* ]]; then
+  if [[ " $* " != *" --help "* ]] && [[ " $* " != *" -h "* ]]; then
     return 1
   fi
 }
 
 calling-complete() {
-  if [[ " $@ " != *" --complete "* ]]; then
+  if [[ " $* " != *" --complete "* ]]; then
     return 1
   fi
 }
diff --git a/libexec/tmuxifier-alias b/libexec/tmuxifier-alias
index 94e4f7e..4265770 100755
--- a/libexec/tmuxifier-alias
+++ b/libexec/tmuxifier-alias
@@ -14,33 +14,37 @@ Resolve a command alias to it's full name."
 fi
 
 case "$1" in
-  "session" | "ses" | "s" )
+  "session" | "ses" | "s")
     echo "load-session"
     ;;
-  "window" | "win" | "w" )
+  "window" | "win" | "w")
     echo "load-window"
     ;;
-  "new-ses" | "nses" | "ns" )
+  "new-ses" | "nses" | "ns")
     echo "new-session"
     ;;
-  "new-win" | "nwin" | "nw" )
+  "new-win" | "nwin" | "nw")
     echo "new-window"
     ;;
-  "edit-ses" | "eses" | "es" )
+  "edit-ses" | "eses" | "es")
     echo "edit-session"
     ;;
-  "edit-win" | "ewin" | "ew" )
+  "edit-win" | "ewin" | "ew")
     echo "edit-window"
     ;;
-  "l" )
+  "l")
     echo "list"
     ;;
-  "list-ses" | "lses" | "ls" )
+  "list-ses" | "lses" | "ls")
     echo "list-sessions"
     ;;
-  "list-win" | "lwin" | "lw" )
+  "list-win" | "lwin" | "lw")
     echo "list-windows"
     ;;
-  * )
+  "completion")
+    echo "completions"
+    ;;
+  *)
     exit 1
+    ;;
 esac
diff --git a/libexec/tmuxifier-commands b/libexec/tmuxifier-commands
index 9de81aa..5f9fd2b 100755
--- a/libexec/tmuxifier-commands
+++ b/libexec/tmuxifier-commands
@@ -16,7 +16,8 @@ fi
 
 shopt -s nullglob
 
-{ for path in ${PATH//:/$'\n'}; do
+{
+  for path in ${PATH//:/$'\n'}; do
     for command in "${path}/tmuxifier-"*; do
       command="${command##*tmuxifier-}"
       echo "$command"
diff --git a/libexec/tmuxifier-completions b/libexec/tmuxifier-completions
index 4408275..45844fa 100755
--- a/libexec/tmuxifier-completions
+++ b/libexec/tmuxifier-completions
@@ -7,7 +7,9 @@ source "$TMUXIFIER/lib/util.sh"
 
 # Provide tmuxifier help
 if calling-help "$@"; then
-  echo "usage: tmuxifier completion <command>
+  echo "usage: tmuxifier completions <command>
+
+Aliases: completion
 
 Print a list of available completions for specified command."
   exit
@@ -20,15 +22,15 @@ if calling-complete "$@"; then
 fi
 
 has-completions() {
-  grep -i "^# Provide tmuxifier completions" "$1" >/dev/null
+  grep -i "^# Provide tmuxifier completions" "$1" > /dev/null
 }
 
 if [ -z "$1" ]; then
-  echo "$(tmuxifier-help completions $@)" >&2
+  tmuxifier-help completions "$@" >&2
   exit 1
 fi
 
-! command_path="$(tmuxifier-resolve-command-path "$1")"
+command_path="$(tmuxifier-resolve-command-path "$1")" || true
 
 if [ -n "$command_path" ] && has-completions "$command_path"; then
   shift
diff --git a/libexec/tmuxifier-current-session b/libexec/tmuxifier-current-session
index 82e09ea..27dc96f 100755
--- a/libexec/tmuxifier-current-session
+++ b/libexec/tmuxifier-current-session
@@ -14,8 +14,8 @@ Outputs the name of the current Tmux session."
 fi
 
 if [ -n "$TMUX" ]; then
-  for item in $(tmuxifier-tmux list-pane -F "#{session_name}");do
-    echo $item
+  for item in $(tmuxifier-tmux list-pane -F "#{session_name}"); do
+    echo "$item"
     exit 0
   done
 fi
diff --git a/libexec/tmuxifier-edit-session b/libexec/tmuxifier-edit-session
index e0722d1..9dad083 100755
--- a/libexec/tmuxifier-edit-session
+++ b/libexec/tmuxifier-edit-session
@@ -22,7 +22,7 @@ if calling-complete "$@"; then
 fi
 
 if [ -z "$1" ]; then
-  echo "$(tmuxifier-help edit-session $@)" >&2
+  tmuxifier-help edit-session "$@" >&2
   exit 1
 fi
 
diff --git a/libexec/tmuxifier-edit-window b/libexec/tmuxifier-edit-window
index dee2986..f01420d 100755
--- a/libexec/tmuxifier-edit-window
+++ b/libexec/tmuxifier-edit-window
@@ -22,7 +22,7 @@ if calling-complete "$@"; then
 fi
 
 if [ -z "$1" ]; then
-  echo "$(tmuxifier-help edit-window $@)" >&2
+  tmuxifier-help edit-window "$@" >&2
   exit 1
 fi
 
diff --git a/libexec/tmuxifier-help b/libexec/tmuxifier-help
index 5c27f1b..edceb53 100755
--- a/libexec/tmuxifier-help
+++ b/libexec/tmuxifier-help
@@ -18,7 +18,7 @@ if calling-complete "$@"; then
 fi
 
 has-help() {
-  grep -i "^# Provide tmuxifier help" "$1" >/dev/null
+  grep -i "^# Provide tmuxifier help" "$1" > /dev/null
 }
 
 if [ -z "$1" ]; then
@@ -43,7 +43,7 @@ See 'tmuxifier help <command>' for information on a specific command."
   exit
 fi
 
-! command_path="$(tmuxifier-resolve-command-path "$1")"
+command_path="$(tmuxifier-resolve-command-path "$1")" || true
 
 if [ -z "$command_path" ]; then
   echo "tmuxifier: no such command '$1'" >&2
diff --git a/libexec/tmuxifier-init b/libexec/tmuxifier-init
index 0bad316..7bd5dbc 100755
--- a/libexec/tmuxifier-init
+++ b/libexec/tmuxifier-init
@@ -2,6 +2,9 @@
 set -e
 [ -n "$TMUXIFIER_DEBUG" ] && set -x
 
+# Load internal utility functions.
+source "$TMUXIFIER/lib/util.sh"
+
 # Set shell to first argument that is not "-", "-h" or "--help".
 for arg in "$@"; do
   if [ "$arg" != "-" ] && [ "$arg" != "-h" ] && [ "$arg" != "--help" ]; then
@@ -14,46 +17,46 @@ if [ -z "$shell" ]; then
 fi
 
 case "$shell" in
-  bash )
-    profile='~/.bash_profile'
+  bash)
+    profile='.bash_profile'
     ;;
-  zsh )
-    profile='~/.zshrc'
+  zsh)
+    profile='.zshrc'
     ;;
-  ksh )
-    profile='~/.profile'
+  ksh)
+    profile='.profile'
     ;;
-  csh )
-    profile='~/.cshrc'
+  csh)
+    profile='.cshrc'
     ;;
-  tcsh )
-    profile='~/.tcshrc'
+  tcsh)
+    profile='.tcshrc'
     ;;
-  fish )
-    profile='~/.config/fish/config.fish'
+  fish)
+    profile='.config/fish/config.fish'
     ;;
-  * )
+  *)
     profile='shell init file'
     ;;
 esac
 
 # Provide tmuxifier help
-if [[ " $@ " == *" --help "* ]]; then
+if calling-help "$@"; then
   echo "usage: tmuxifier init -
 
-Load Tmuxifier by adding the following to your ${profile}:
+Load Tmuxifier by adding the following to your ~/${profile}:
 "
 
   case "$shell" in
-    csh | tcsh )
+    csh | tcsh)
       echo "    eval \`tmuxifier init -\`
 "
       ;;
-    fish )
+    fish)
       echo "    eval (tmuxifier init -)
 "
       ;;
-    * )
+    *)
       echo "    eval \"\$(tmuxifier init -)\"
 "
       ;;
@@ -64,26 +67,26 @@ Load Tmuxifier by adding the following to your ${profile}:
 fi
 
 # Print help if "-" argument is not given
-if [[ " $@ " != *" - "* ]]; then
-  echo "$(tmuxifier-help init $@)" >&2
+if [[ " $* " != *" - "* ]]; then
+  tmuxifier-help init "$@" >&2
   exit 1
 fi
 
 case "$shell" in
-  csh | tcsh )
+  csh | tcsh)
     echo "setenv TMUXIFIER \"$TMUXIFIER\";"
     echo "source \"\$TMUXIFIER/init.tcsh\";"
     ;;
-  fish )
+  fish)
     echo "set -gx TMUXIFIER \"$TMUXIFIER\";"
     # fish shell 2.0.0 does not have the source alias
     if [[ $(fish --version 2>&1 | awk -F'version ' '{print $2}') = '2.0.0' ]]; then
       echo ". \"\$TMUXIFIER/init.fish\";"
     else
       echo "source \"\$TMUXIFIER/init.fish\";"
-    fi  
+    fi
     ;;
-  * )
+  *)
     echo "export TMUXIFIER=\"$TMUXIFIER\";"
     echo "source \"\$TMUXIFIER/init.sh\";"
     ;;
diff --git a/libexec/tmuxifier-load-session b/libexec/tmuxifier-load-session
index 5083b4f..318f875 100755
--- a/libexec/tmuxifier-load-session
+++ b/libexec/tmuxifier-load-session
@@ -30,7 +30,7 @@ if calling-complete "$@"; then
 fi
 
 if [ -z "$1" ]; then
-  echo "$(tmuxifier-help load-session $@)" >&2
+  tmuxifier-help load-session "$@" >&2
   exit 1
 fi
 
diff --git a/libexec/tmuxifier-load-window b/libexec/tmuxifier-load-window
index 0a6d0f9..772ac41 100755
--- a/libexec/tmuxifier-load-window
+++ b/libexec/tmuxifier-load-window
@@ -26,14 +26,14 @@ if calling-complete "$@"; then
 fi
 
 if [ -z "$1" ]; then
-  echo "$(tmuxifier-help load-window $@)" >&2
+  tmuxifier-help load-window "$@" >&2
   exit 1
 fi
 
 # Load runtime functions.
 source "$TMUXIFIER/lib/runtime.sh"
 
-if [ ! -z $TMUX ]; then
+if [ -n "$TMUX" ]; then
   session="$(tmuxifier-current-session)"
   load_window "$1"
 else
diff --git a/libexec/tmuxifier-new-session b/libexec/tmuxifier-new-session
index c3ec25f..4de01d2 100755
--- a/libexec/tmuxifier-new-session
+++ b/libexec/tmuxifier-new-session
@@ -22,7 +22,7 @@ if calling-complete "$@"; then
 fi
 
 if [ -z "$1" ]; then
-  echo "$(tmuxifier-help new-session $@)" >&2
+  tmuxifier-help new-session "$@" >&2
   exit 1
 fi
 
diff --git a/libexec/tmuxifier-new-window b/libexec/tmuxifier-new-window
index a9e35ef..f4be1ae 100755
--- a/libexec/tmuxifier-new-window
+++ b/libexec/tmuxifier-new-window
@@ -22,7 +22,7 @@ if calling-complete "$@"; then
 fi
 
 if [ -z "$1" ]; then
-  echo "$(tmuxifier-help new-window $@)" >&2
+  tmuxifier-help new-window "$@" >&2
   exit 1
 fi
 
diff --git a/libexec/tmuxifier-resolve-command-path b/libexec/tmuxifier-resolve-command-path
index 6eeec67..7701eb5 100755
--- a/libexec/tmuxifier-resolve-command-path
+++ b/libexec/tmuxifier-resolve-command-path
@@ -14,11 +14,11 @@ Outputs the absolute path to the given command or command alias."
 fi
 
 if [ -n "$1" ]; then
-  ! command_path="$(command -v "tmuxifier-$1")"
+  command_path="$(command -v "tmuxifier-$1")" || true
   if [ -z "$command_path" ]; then
     resolved="$(tmuxifier-alias "$1")"
     if [ -n "$resolved" ]; then
-      ! command_path="$(command -v "tmuxifier-$resolved")"
+      command_path="$(command -v "tmuxifier-$resolved")" || true
     fi
   fi
 fi
diff --git a/libexec/tmuxifier-tmux b/libexec/tmuxifier-tmux
index 96328a6..785e0ba 100755
--- a/libexec/tmuxifier-tmux
+++ b/libexec/tmuxifier-tmux
@@ -2,4 +2,5 @@
 set -e
 [ -n "$TMUXIFIER_DEBUG" ] && set -x
 
+# shellcheck disable=SC2086
 tmux $TMUXIFIER_TMUX_OPTS "$@"
diff --git a/libexec/tmuxifier-tmux-version b/libexec/tmuxifier-tmux-version
index f48b17e..c1cadc8 100755
--- a/libexec/tmuxifier-tmux-version
+++ b/libexec/tmuxifier-tmux-version
@@ -19,16 +19,17 @@ fi
 
 # The vercomp() function is shamelessly ripped/borrowed from the following
 # StackOverflow answer: http://stackoverflow.com/a/4025065/42146
-vercomp () {
-  if [[ $1 == $2 ]]; then return 0; fi
+vercomp() {
+  if [[ "$1" == "$2" ]]; then return 0; fi
 
   local IFS=.
+  # shellcheck disable=SC2206
   local i ver1=($1) ver2=($2)
 
   # fill empty fields in ver1 with zeros
-  for ((i=${#ver1[@]}; i<${#ver2[@]}; i++)); do ver1[i]=0; done
+  for ((i = ${#ver1[@]}; i < ${#ver2[@]}; i++)); do ver1[i]=0; done
 
-  for ((i=0; i<${#ver1[@]}; i++)); do
+  for ((i = 0; i < ${#ver1[@]}; i++)); do
     # fill empty fields in ver2 with zeros
     if [[ -z ${ver2[i]} ]]; then ver2[i]=0; fi
 
@@ -63,8 +64,8 @@ else
 
   vercomp "$version" "$1"
   case $? in
-    0) echo '=';;
-    1) echo '>';;
-    2) echo '<';;
+    0) echo '=' ;;
+    1) echo '>' ;;
+    2) echo '<' ;;
   esac
 fi
diff --git a/test/lib/env.test.sh b/test/lib/env.test.sh
index 0caf1c0..321a25f 100755
--- a/test/lib/env.test.sh
+++ b/test/lib/env.test.sh
@@ -11,21 +11,25 @@ TMUXIFER="/path/to/tmuxifier"
 
 # When TMUXIFIER_LAYOUT_PATH is not set.
 source "${root}/lib/env.sh"
+# shellcheck disable=SC2016
 assert 'echo $TMUXIFIER_LAYOUT_PATH' "${TMUXIFIER}/layouts"
 
 # When TMUXIFIER_LAYOUT_PATH is set and has a trailing slash.
 TMUXIFIER_LAYOUT_PATH="/path/to/layouts/"
 source "${root}/lib/env.sh"
+# shellcheck disable=SC2016
 assert 'echo $TMUXIFIER_LAYOUT_PATH' "/path/to/layouts"
 unset TMUXIFIER_LAYOUT_PATH
 
 # When TMUXIFIER_LAYOUT_PATH is set and does not have a trailing slash.
 TMUXIFIER_LAYOUT_PATH="/path/to/layouts"
 source "${root}/lib/env.sh"
+# shellcheck disable=SC2016
 assert 'echo $TMUXIFIER_LAYOUT_PATH' "/path/to/layouts"
 unset TMUXIFIER_LAYOUT_PATH
 
 # Tear down.
+# shellcheck disable=SC2034
 TMUXIFER="$realTMUXIFIER"
 unset realTMUXIFIER
 
diff --git a/test/lib/layout-helpers/__get_current_window_index.test.sh b/test/lib/layout-helpers/__get_current_window_index.test.sh
index cf4371c..bed8710 100755
--- a/test/lib/layout-helpers/__get_current_window_index.test.sh
+++ b/test/lib/layout-helpers/__get_current_window_index.test.sh
@@ -7,25 +7,25 @@ source "${root}/lib/layout-helpers.sh"
 #
 
 # When current window is the first and only window.
-create-test-session
+create-test-session "test"
 assert "__get_current_window_index" "0"
-kill-test-session
+kill-test-session "test"
 
 # When creating a second window.
-create-test-session
+create-test-session "test"
 test-socket-tmux new-window -t "$session:1"
 assert "__get_current_window_index" "1"
-kill-test-session
+kill-test-session "test"
 
 # When creating a second window and then switching back to the first window.
-create-test-session
+create-test-session "test"
 test-socket-tmux new-window -t "$session:1"
 test-socket-tmux select-window -t "$session:0"
 assert "__get_current_window_index" "0"
-kill-test-session
+kill-test-session "test"
 
 # When creating multiples windows and switching between them randomly.
-create-test-session
+create-test-session "test"
 assert "__get_current_window_index" "0"
 test-socket-tmux new-window -t "$session:1"
 assert "__get_current_window_index" "1"
@@ -41,8 +41,7 @@ test-socket-tmux select-window -t "$session:3"
 assert "__get_current_window_index" "3"
 test-socket-tmux select-window -t "$session:2"
 assert "__get_current_window_index" "2"
-kill-test-session
-
+kill-test-session "test"
 
 # End of tests.
 assert_end "__get_current_window_index()"
diff --git a/test/lib/layout-helpers/__get_first_window_index.test.sh b/test/lib/layout-helpers/__get_first_window_index.test.sh
index c08dfd4..5eca447 100755
--- a/test/lib/layout-helpers/__get_first_window_index.test.sh
+++ b/test/lib/layout-helpers/__get_first_window_index.test.sh
@@ -7,24 +7,23 @@ source "${root}/lib/layout-helpers.sh"
 #
 
 # When first window has a index of 0.
-create-test-session
+create-test-session "test"
 assert "__get_first_window_index" "0"
-kill-test-session
+kill-test-session "test"
 
 # When first window has a index of 1.
-create-test-session
+create-test-session "test"
 test-socket-tmux new-window -t "$session:1"
 test-socket-tmux kill-window -t "$session:0"
 assert "__get_first_window_index" "1"
-kill-test-session
+kill-test-session "test"
 
 # When first window has a index of 2.
-create-test-session
+create-test-session "test"
 test-socket-tmux new-window -t "$session:2"
 test-socket-tmux kill-window -t "$session:0"
 assert "__get_first_window_index" "2"
-kill-test-session
-
+kill-test-session "test"
 
 # End of tests.
 assert_end "__get_first_window_index()"
diff --git a/test/lib/layout-helpers/__go_to_window_or_session_path.test.sh b/test/lib/layout-helpers/__go_to_window_or_session_path.test.sh
index bdb5e2c..d0a774e 100755
--- a/test/lib/layout-helpers/__go_to_window_or_session_path.test.sh
+++ b/test/lib/layout-helpers/__go_to_window_or_session_path.test.sh
@@ -12,7 +12,6 @@ __go_to_window_or_session_path
 assert "stub_called_times run_cmd" "0"
 restore run_cmd
 
-
 # When only $window_root is set, runs cd to $window_root path.
 stub run_cmd
 window_root="/tmp"
@@ -22,7 +21,6 @@ assert 'stub_called_with_times run_cmd clear' "1"
 unset window_root
 restore run_cmd
 
-
 # When only $TMUXIFIER_SESSION_ROOT is set, runs cd to $TMUXIFIER_SESSION_ROOT
 # path.
 stub run_cmd
@@ -33,7 +31,6 @@ assert 'stub_called_with_times run_cmd clear' "1"
 unset TMUXIFIER_SESSION_ROOT
 restore run_cmd
 
-
 # When only $session_root is set, runs cd to $session_root path.
 stub run_cmd
 session_root="/usr"
@@ -43,7 +40,6 @@ assert 'stub_called_with_times run_cmd clear' "1"
 unset session_root
 restore run_cmd
 
-
 # When $window_root and $session_root are set, runs cd to $window_root path.
 stub run_cmd
 window_root="/tmp"
@@ -55,7 +51,6 @@ unset window_root
 unset session_root
 restore run_cmd
 
-
 # When $TMUXIFIER_SESSION_ROOT and $session_root are set, runs cd to
 # $TMUXIFIER_SESSION_ROOT path.
 stub run_cmd
@@ -68,7 +63,6 @@ unset TMUXIFIER_SESSION_ROOT
 unset session_root
 restore run_cmd
 
-
 # When $window_root, $TMUXIFIER_SESSION_ROOT, and $session_root are set, runs
 # cd to $window_root path.
 stub run_cmd
@@ -83,6 +77,5 @@ unset TMUXIFIER_SESSION_ROOT
 unset session_root
 restore run_cmd
 
-
 # End of tests.
 assert_end "__go_to_window_or_session_path()"
diff --git a/test/lib/layout-helpers/new_window.test.sh b/test/lib/layout-helpers/new_window.test.sh
index 21a601f..4772a87 100755
--- a/test/lib/layout-helpers/new_window.test.sh
+++ b/test/lib/layout-helpers/new_window.test.sh
@@ -7,29 +7,29 @@ source "${root}/lib/layout-helpers.sh"
 #
 
 # When called without arguments, creates new window.
-create-test-session
+create-test-session "test"
 stub __go_to_window_or_session_path
 assert "test-socket-window-count" "1"
 new_window
 assert "test-socket-window-count" "2"
 assert "stub_called_times __go_to_window_or_session_path" "1"
 restore __go_to_window_or_session_path
-kill-test-session
+kill-test-session "test"
 
 # When called with name argument, creates new window with specified name.
-create-test-session
+create-test-session "test"
 stub __go_to_window_or_session_path
 assert "test-socket-window-count yippieezzz" "0"
 new_window "yippieezzz"
 assert "test-socket-window-count" "2"
 assert "test-socket-window-count yippieezzz" "1"
 restore __go_to_window_or_session_path
-kill-test-session
+kill-test-session "test"
 
 # When called with name and command argument, creates new window with
 # specified name and executes given command.
 rm "/tmp/tmuxifier-new_window-test" &> /dev/null
-create-test-session
+create-test-session "test"
 stub __go_to_window_or_session_path
 new_window "foobardoo" "touch /tmp/tmuxifier-new_window-test; bash"
 assert "test-socket-window-count" "2"
@@ -37,13 +37,13 @@ assert "test-socket-window-count foobardoo" "1"
 sleep 0.1 # attempt to avoid timing issue causing flicker
 assert_raises 'test -f "/tmp/tmuxifier-new_window-test"' 0
 restore __go_to_window_or_session_path
-kill-test-session
+kill-test-session "test"
 rm "/tmp/tmuxifier-new_window-test" &> /dev/null
 
 # When called ensure it sets the $window variable to the index of the newly
 # created window.
 unset window
-create-test-session
+create-test-session "test"
 stub __go_to_window_or_session_path
 new_window "foo"
 assert "echo $window" "1"
@@ -52,7 +52,7 @@ assert "echo $window" "2"
 new_window "bar"
 assert "echo $window" "3"
 restore __go_to_window_or_session_path
-kill-test-session
+kill-test-session "test"
 unset window
 
 # End of tests.
diff --git a/test/lib/layout-helpers/select_window.test.sh b/test/lib/layout-helpers/select_window.test.sh
index 0ba4977..ba023af 100755
--- a/test/lib/layout-helpers/select_window.test.sh
+++ b/test/lib/layout-helpers/select_window.test.sh
@@ -8,11 +8,11 @@ source "${root}/lib/layout-helpers.sh"
 
 window_list() {
   test-socket-tmux list-windows -t "$session:" \
-    -F "#{window_active}:#{window_index}" 2>/dev/null
+    -F "#{window_active}:#{window_index}" 2> /dev/null
 }
 
 # Selects given window when passed a window index
-create-test-session
+create-test-session "test"
 test-socket-tmux new-window -t "$session:1"
 test-socket-tmux new-window -t "$session:2"
 select_window 0
@@ -21,23 +21,22 @@ select_window 1
 assert "window_list | grep '^1:'" "1:1"
 select_window 2
 assert "window_list | grep '^1:'" "1:2"
-kill-test-session
+kill-test-session "test"
 
 # Selects given window when passed a window name
-create-test-session
+create-test-session "test"
 test-socket-tmux new-window -t "$session:1" -n "foo"
 test-socket-tmux new-window -t "$session:2" -n "bar"
 select_window foo
 assert "window_list | grep '^1:'" "1:1"
 select_window bar
 assert "window_list | grep '^1:'" "1:2"
-kill-test-session
-
+kill-test-session "test"
 
 # When called ensure it sets the $window variable to the index of the newly
 # created window.
 unset window
-create-test-session
+create-test-session "test"
 test-socket-tmux new-window -t "$session:1" -n "foo"
 test-socket-tmux new-window -t "$session:2" -n "bar"
 select_window "foo"
@@ -48,7 +47,7 @@ select_window 1
 assert "echo $window" "1"
 select_window 2
 assert "echo $window" "2"
-kill-test-session
+kill-test-session "test"
 unset window
 
 # End of tests.
diff --git a/test/lib/runtime.test.sh b/test/lib/runtime.test.sh
index 06d5a68..72f86f0 100755
--- a/test/lib/runtime.test.sh
+++ b/test/lib/runtime.test.sh
@@ -8,9 +8,11 @@ source "../test-helper.sh"
 source "${root}/lib/runtime.sh"
 
 # We assume env.sh has been sourced if $TMUXIFIER_LAYOUT_PATH has been set.
+# shellcheck disable=SC2016
 assert 'echo $TMUXIFIER_LAYOUT_PATH' "${TMUXIFIER}/layouts"
 
 # We ensure $session_root is set to $HOME by default.
+# shellcheck disable=SC2016
 assert 'echo $session_root' "$HOME"
 
 # We assume layout-helpers.sh has been sourced if a few of them are available.
@@ -18,6 +20,5 @@ for helper in new_window split_v split_h select_window select_pane; do
   assert "type $helper | head -1" "$helper is a function"
 done
 
-
 # End of tests.
 assert_end "runtime.sh"
diff --git a/test/lib/util.test.sh b/test/lib/util.test.sh
index df6cc08..cebc6ef 100755
--- a/test/lib/util.test.sh
+++ b/test/lib/util.test.sh
@@ -34,7 +34,6 @@ assert_raises 'calling-help welcome-home' 1
 # End of tests.
 assert_end "calling-help()"
 
-
 #
 # calling-complete() tests.
 #
diff --git a/test/test-helper.sh b/test/test-helper.sh
index ed081be..ab5acdf 100644
--- a/test/test-helper.sh
+++ b/test/test-helper.sh
@@ -5,8 +5,9 @@ resolve_link() {
 }
 
 abs_dirname() {
-  local cwd="$(pwd)"
+  local cwd
   local path="$1"
+  cwd="$(pwd)"
 
   while [ -n "$path" ]; do
     cd "${path%/*}"
@@ -47,14 +48,13 @@ unset TMUXIFIER_NO_COMPLETE
 source "${testroot}/assert.sh"
 source "${testroot}/stub.sh"
 
-
 #
 # Test Helpers
 #
 
 test-socket-tmux() {
   export TMUXIFIER_TMUX_OPTS="-L tmuxifier-tests"
-  "$TMUX_BIN" $TMUXIFIER_TMUX_OPTS $@
+  "$TMUX_BIN" $TMUXIFIER_TMUX_OPTS "$@"
 }
 
 create-test-session() {
@@ -78,9 +78,10 @@ kill-test-server() {
 }
 
 test-socket-window-count() {
-  local list="$(test-socket-tmux list-windows)"
+  local list
+  list="$(test-socket-tmux list-windows)"
   if [ -n "$1" ]; then
-    echo "$list" | grep $1 | wc -l | awk '{print $1}'
+    echo "$list" | grep "$1" -c | awk '{print $1}'
   else
     echo "$list" | wc -l | awk '{print $1}'
   fi