diff --git a/src/arg.sh b/src/arg.sh
index b93d691..c3c2165 100644
--- a/src/arg.sh
+++ b/src/arg.sh
@@ -11,8 +11,8 @@ arg::opts() {
 }
 
 arg::interpolate() {
-   local readonly arg="$1"
-   local readonly value="$2"
+   local -r arg="$1"
+   local -r value="$2"
 
    sed "s|<${arg}>|\"${value}\"|g"
 }
@@ -25,15 +25,15 @@ arg::next() {
 }
 
 arg::pick() {
-   local readonly arg="$1"
-   local readonly cheat="$2"
+   local -r arg="$1"
+   local -r cheat="$2"
 
-   local readonly prefix="$ ${arg}:"
-   local readonly length="$(echo "$prefix" | str::length)"
-   local readonly arg_description="$(grep "$prefix" "$cheat" | str::sub $((length + 1)))"
+   local -r prefix="$ ${arg}:"
+   local -r length="$(echo "$prefix" | str::length)"
+   local -r arg_description="$(grep "$prefix" "$cheat" | str::sub $((length + 1)))"
 
-   local readonly fn="$(echo "$arg_description" | arg::fn)"
-   local readonly args_str="$(echo "$arg_description" | arg::opts | tr ' ' '\n' || echo "")"
+   local -r fn="$(echo "$arg_description" | arg::fn)"
+   local -r args_str="$(echo "$arg_description" | arg::opts | tr ' ' '\n' || echo "")"
    local arg_name=""
 
    for arg_str in $args_str; do
diff --git a/src/cheat.sh b/src/cheat.sh
index 4ff6967..1817147 100755
--- a/src/cheat.sh
+++ b/src/cheat.sh
@@ -21,10 +21,10 @@ cheat::read_many() {
 }
 
 cheat::from_selection() {
-   local readonly cheats="$1"
-   local readonly selection="$2"
+   local -r cheats="$1"
+   local -r selection="$2"
 
-   local readonly tags="$(echo "$selection" | selection::tags)"
+   local -r tags="$(echo "$selection" | selection::tags)"
 
    for cheat in $cheats; do
       if grep -q "% $tags" "$cheat"; then
diff --git a/src/main.sh b/src/main.sh
index faf085e..45977cd 100644
--- a/src/main.sh
+++ b/src/main.sh
@@ -11,9 +11,9 @@ source "${SCRIPT_DIR}/src/str.sh"
 source "${SCRIPT_DIR}/src/ui.sh"
 
 handler::main() {
-   local readonly cheats="$(cheat::find)"
-   local readonly selection="$(ui::select "$cheats")"
-   local readonly cheat="$(cheat::from_selection "$cheats" "$selection")"
+   local -r cheats="$(cheat::find)"
+   local -r selection="$(ui::select "$cheats")"
+   local -r cheat="$(cheat::from_selection "$cheats" "$selection")"
    [ -z "$cheat" ] && exit 67
    local cmd="$(selection::command "$selection" "$cheat")"
    local arg value
@@ -34,7 +34,7 @@ handler::main() {
       cmd="$(echo "$cmd" | arg::interpolate "$arg" "$value")"
    done
 
-   local readonly unresolved_arg="$(echo "$cmd" | arg::next || echo "")"
+   local -r unresolved_arg="$(echo "$cmd" | arg::next || echo "")"
 
    if $print || [ -n "$unresolved_arg" ]; then
       echo "$cmd"
@@ -44,9 +44,9 @@ handler::main() {
 }
 
 handler::preview() {
-   local readonly selection="$(echo "$query" | selection::standardize)"
-   local readonly cheats="$(cheat::find)"
-   local readonly cheat="$(cheat::from_selection "$cheats" "$selection")"
+   local -r selection="$(echo "$query" | selection::standardize)"
+   local -r cheats="$(cheat::find)"
+   local -r cheat="$(cheat::from_selection "$cheats" "$selection")"
    [ -n "$cheat" ] && selection::command "$selection" "$cheat"
 }
 
diff --git a/src/opts.sh b/src/opts.sh
index 04b218d..453998a 100644
--- a/src/opts.sh
+++ b/src/opts.sh
@@ -2,12 +2,12 @@
 set -euo pipefail
 
 opts::extract_help() {
-   local readonly file="$1"
+   local -r file="$1"
    grep "^##?" "$file" | cut -c 5-
 }
 
 opts::preview_hack() {
-   local readonly arg="$1"
+   local -r arg="$1"
 
    if [ ${arg:0:1} = "'" ]; then
       echo "${arg:1:${#arg}-2}"
@@ -17,7 +17,7 @@ opts::preview_hack() {
 }
 
 opts::eval() {
-   local readonly wait_for=""
+   local -r wait_for=""
 
    entry_point="main"
    print=false
diff --git a/src/search.sh b/src/search.sh
index 1b9bfbc..f611e0b 100644
--- a/src/search.sh
+++ b/src/search.sh
@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 
 search::cheat() {
-   local readonly cmd="$(echo "$1" | str::first_word)"
+   local -r cmd="$(echo "$1" | str::first_word)"
 
    echo "% ${cmd}, cheatsh"
    echo
@@ -9,7 +9,7 @@ search::cheat() {
 }
 
 search::filename() {
-   local readonly cmd="$(echo "$1" | str::first_word)"
+   local -r cmd="$(echo "$1" | str::first_word)"
 
    echo "${cmd}_cheatsh" \
       | head -n1 \
@@ -19,16 +19,16 @@ search::filename() {
 }
 
 search::full_path() {
-   local readonly cmd="$(echo "$1" | str::first_word)"
+   local -r cmd="$(echo "$1" | str::first_word)"
 
    echo "/tmp/navi/$(search::filename "$cmd").cheat"
 }
 
 search::save() {
-   local readonly cmd="$(echo "$1" | str::first_word)"
+   local -r cmd="$(echo "$1" | str::first_word)"
 
-   local readonly filepath="$(search::full_path "$cmd")"
-   local readonly filedir="$(dirname "$filepath")"
+   local -r filepath="$(search::full_path "$cmd")"
+   local -r filedir="$(dirname "$filepath")"
 
    if [ -f "$filepath" ]; then
       return
diff --git a/src/selection.sh b/src/selection.sh
index 481df15..9f10ca8 100644
--- a/src/selection.sh
+++ b/src/selection.sh
@@ -1,10 +1,10 @@
 #!/usr/bin/env bash
 
 selection::standardize() {
-   local readonly str="$(cat)"
+   local -r str="$(cat)"
 
-   local readonly tags="$(echo "$str" | awk -F'[' '{print $NF}' | tr -d ']')"
-   local readonly core="$(echo "$str" | sed -e "s/ \[${tags}\]$//")"
+   local -r tags="$(echo "$str" | awk -F'[' '{print $NF}' | tr -d ']')"
+   local -r core="$(echo "$str" | sed -e "s/ \[${tags}\]$//")"
 
    echo "${core}^${tags}"
 }
@@ -22,10 +22,10 @@ selection::core_is_comment() {
 }
 
 selection::command() {
-   local readonly selection="$1"
-   local readonly cheat="$2"
+   local -r selection="$1"
+   local -r cheat="$2"
 
-   local readonly core="$(echo $selection | selection::core)"
+   local -r core="$(echo $selection | selection::core)"
 
    if echo "$core" | selection::core_is_comment; then
       grep "$core" "$cheat" -A999 \
diff --git a/src/str.sh b/src/str.sh
index 6e860b6..f58e962 100644
--- a/src/str.sh
+++ b/src/str.sh
@@ -5,14 +5,14 @@ str::length() {
 }
 
 str::sub() {
-   local readonly start="${1:-0}"
-   local readonly finish="${2:-99999}"
+   local -r start="${1:-0}"
+   local -r finish="${2:-99999}"
 
    cut -c "$((start + 1))-$((finish - 1))"
 }
 
 str::column() {
-   local readonly n="${1:-}"
+   local -r n="${1:-}"
 
    if [ -n "$n" ]; then
       awk "{print \$$n}"
diff --git a/src/ui.sh b/src/ui.sh
index c8ab0a0..0cf8e7f 100644
--- a/src/ui.sh
+++ b/src/ui.sh
@@ -5,9 +5,9 @@ ui::pick() {
 }
 
 ui::select() {
-   local readonly cheats="$1"
-   local readonly script_path="$(which navi | head -n1 || echo "${SCRIPT_DIR}/navi")"
-   local readonly preview_cmd="echo \"{}\" | tr ' ' '^' | xargs -I% \"${script_path}\" preview %"
+   local -r cheats="$1"
+   local -r script_path="$(which navi | head -n1 || echo "${SCRIPT_DIR}/navi")"
+   local -r preview_cmd="echo \"{}\" | tr ' ' '^' | xargs -I% \"${script_path}\" preview %"
 
    local args=()
    args+=("-i")