diff --git a/git/install.sh b/git/install.sh
index a063b42..4998b95 100644
--- a/git/install.sh
+++ b/git/install.sh
@@ -4,20 +4,21 @@ set -u
 
 __init_git() {
 
-    if [ -z "$(command -v git)" ]; then
-        if [ "Darwin" = "$(uname -s)" ]; then
-            echo >&2 "Error: 'git' not found. You may have to re-install 'git' on Mac after every major update."
-            echo >&2 "       for example, try: xcode-select --install"
-            # sudo xcodebuild -license accept
-        else
-            echo >&2 "Error: to install 'git' on Linux use the built-in package manager."
-            echo >&2 "       for example, try: sudo apt install -y git"
-        fi
-        exit 1
-    else
+    if command -v git > /dev/null; then
         echo "'git' already installed"
+        return 0
     fi
 
+    if [ "Darwin" = "$(uname -s)" ]; then
+        echo >&2 "Error: 'git' not found. You may have to re-install 'git' on Mac after every major update."
+        echo >&2 "       for example, try: xcode-select --install"
+        # sudo xcodebuild -license accept
+    else
+        echo >&2 "Error: to install 'git' on Linux use the built-in package manager."
+        echo >&2 "       for example, try: sudo apt install -y git"
+    fi
+
+    exit 1
 }
 
 __init_git
diff --git a/pyenv/install.sh b/pyenv/install.sh
index 6f67147..2ba8ef7 100644
--- a/pyenv/install.sh
+++ b/pyenv/install.sh
@@ -17,7 +17,7 @@ __init_pyenv() {
         } >> ~/.bashrc
     fi
 
-    if [ -n "$(command -v zsh)" ]; then
+    if command -v zsh > /dev/null; then
         touch ~/.zshrc
         if ! grep -q 'pyenv init' ~/.zshrc; then
             {
@@ -31,7 +31,7 @@ __init_pyenv() {
         fi
     fi
 
-    if [ -n "$(command -v fish)" ]; then
+    if command -v fish > /dev/null; then
         mkdir -p ~/.config/fish
         touch ~/.config/fish/config.fish
         if ! grep -q 'pyenv init' ~/.config/fish/config.fish; then
diff --git a/sudo/install.sh b/sudo/install.sh
index 671a1f4..4f7c33a 100644
--- a/sudo/install.sh
+++ b/sudo/install.sh
@@ -4,14 +4,20 @@ set -u
 
 __init_sudo() {
 
-    if [ -z "$(command -v sudo)" ]; then
-        echo >&2 "Error: on Linux and BSD you should install sudo via the native package manager"
-        echo >&2 "       for example: apt install -y sudo"
-        exit 1
-    else
+    if command -v sudo > /dev/null; then
         echo "'sudo' already installed"
+        exit 0
     fi
 
+    echo >&2 "Error: on Linux & BSD use the native package manager to install sudo:"
+    echo >&2 "    For Ubuntu / Debian:"
+    echo >&2 "       apt install -y sudo"
+    echo >&2 ""
+    echo >&2 "    For Alpine / Docker:"
+    echo >&2 "       apk add sudo"
+    echo >&2 ""
+
+    exit 1
 }
 
 __init_sudo
diff --git a/vim-beyondcode/install.sh b/vim-beyondcode/install.sh
index 0c517d0..24e427f 100644
--- a/vim-beyondcode/install.sh
+++ b/vim-beyondcode/install.sh
@@ -22,7 +22,7 @@ __init_vim_beyondcode() {
         nerdfont \
         vim-devicons
 
-    if [ -n "$(command -v go)" ]; then
+    if command -v go > /dev/null; then
         "$HOME/.local/bin/webi" vim-go
     fi
     # done
diff --git a/vim-prettier/install.sh b/vim-prettier/install.sh
index d26c6a1..e67ee9d 100644
--- a/vim-prettier/install.sh
+++ b/vim-prettier/install.sh
@@ -8,7 +8,7 @@ __init_vim_prettier() {
     rm -rf "$HOME/.vim/pack/plugins/start/vim-prettier"
     git clone --depth=1 https://github.com/prettier/vim-prettier.git "$HOME/.vim/pack/plugins/start/vim-prettier"
 
-    if [ -z "$(command -v node)" ]; then
+    if ! command -v node > /dev/null; then
         export PATH="$HOME/.local/opt/node/bin:$HOME/.local/bin:${PATH}"
         "$HOME/.local/bin/webi" node
     fi
diff --git a/vim-shfmt/install.sh b/vim-shfmt/install.sh
index 350b6a2..1d8949b 100644
--- a/vim-shfmt/install.sh
+++ b/vim-shfmt/install.sh
@@ -9,10 +9,10 @@ __init_vim_shfmt() {
     git clone --depth=1 https://github.com/z0mbix/vim-shfmt.git "$HOME/.vim/pack/plugins/start/vim-shfmt"
 
     export PATH="$HOME/.local/bin:${PATH}"
-    if [ -z "$(command -v shfmt)" ]; then
+    if ! command -v shfmt > /dev/null; then
         "$HOME/.local/bin/webi" shfmt
     fi
-    if [ -z "$(command -v shellcheck)" ]; then
+    if ! command -v shellcheck > /dev/null; then
         "$HOME/.local/bin/webi" shellcheck
     fi