Removing bash specific commands in install script

install

@@ -6,7 +6,7 @@ LOCATION=/usr/local/bin
 # exit top level program from subshell
 trap "exit 1" TERM
 export TOP_PID=$$
-function fail() {
+fail() {
    kill -s TERM $TOP_PID
 }
 
@@ -24,7 +24,7 @@ X64=x64
 AARCH64=aarch64
 
 # returns this platform ID
-function get_this_platform() {
+get_this_platform() {
     local this_platform="$(uname -s)"
     case $this_platform in
         Linux*) echo $LIN ;;
@@ -37,7 +37,7 @@ function get_this_platform() {
 }
 
 # returns this platform architecture
-function get_this_architecture() {
+get_this_architecture() {
     local this_machine="$(uname -m)"
     case $this_machine in
         x86_64) echo $X64 ;;
@@ -55,7 +55,7 @@ THIS_PLATFORM=$(get_this_platform)
 THIS_ARCHITECTURE=$(get_this_architecture)
 
 # fetches latest release download link for the platform
-function get_warp_link() {
+get_warp_link() {
     local this_platform=$1
     local this_architecture=$2
     
@@ -72,13 +72,13 @@ function get_warp_link() {
 }
 
 # downloads and installs single binary
-function install() {
+install() {
     local name=$1
     local link=$2
     local temp_location="/tmp/$name"
     echo "Downloading $name..."
     curl -fsSL -o $temp_location $link
-    if [[ $? != 0 ]]; then
+    if [ $? != 0 ]; then
         echo "Error: Failed to download $name" >&2
         fail
     fi
@@ -88,7 +88,7 @@ function install() {
         --owner=root \
         --group=root \
         "$temp_location" "$LOCATION"
-    if [[ $? != 0 ]]; then
+    if [ $? != 0 ]; then
         echo "Error: Failed to install $name" >&2
         fail
     fi
@@ -96,23 +96,34 @@ function install() {
 }
 
 # returns missing dependencies
-function get_missing_deps() {
-    local deps=( 
-        "awk" \
-        "curl" \
-        "file" \
-        "grep" \
-        "sed" \
-        "sort" \
-        "tar" \
-        "unzip" \
-        "zip" \
-    )
-    for d in ${deps[@]}; do
-        if ! command -v $d &> /dev/null ; then
-            echo -n "$d "
+get_missing_deps() {
+    if ! command -v awk > /dev/null 2<&1; then
+        echo -n "awk "
+    fi
+    if ! command -v curl > /dev/null 2<&1; then
+        echo -n "curl "
+    fi
+    if ! command -v file > /dev/null 2<&1; then
+        echo -n "file "
+    fi
+    if ! command -v grep > /dev/null 2<&1; then
+        echo -n "grep "
+    fi
+    if ! command -v sed > /dev/null 2<&1; then
+        echo -n "sed "
+    fi
+    if ! command -v sort > /dev/null 2<&1; then
+        echo -n "sort "
+    fi
+    if ! command -v tar > /dev/null 2<&1; then
+        echo -n "tar "
+    fi
+    if ! command -v unzip > /dev/null 2<&1; then
+        echo -n "unzip "
+    fi
+    if ! command -v zip > /dev/null 2<&1; then
+        echo -n "zip"
     fi
-    done
 }
 
 WARP4J_LINK="https://git.phoenix.ipv64.de/public/warp4j/raw/branch/master/warp4j"
@@ -125,14 +136,11 @@ MISSING_DEPS=$(get_missing_deps)
 install "warp-packer" "$WARP_LINK" && \
 install "warp4j" "$WARP4J_LINK"
 
-if [[ -z $MISSING_DEPS ]]; then
+if [ -z "$MISSING_DEPS" ]; then
     echo "Successfully installed"
 else
     echo "Main tools successfully installed"
     echo "Please install following with your package manager:"
-    for d in ${MISSING_DEPS[@]}; do
-            echo -n "$d "
-    done
-    echo
+    echo $MISSING_DEPS
     exit 1
 fi