Merge pull request #130 from felipeconti/master

Installing on /usr/local/bin as root

install.sh

@@ -5,6 +5,10 @@ KERNEL=$(uname -s)
 
 function output() { echo -e "\033[32mctop-install\033[0m $@"; }
 
+function command_exists() {
+	command -v "$@" > /dev/null 2>&1
+}
+
 # extract github download url matching pattern
 function extract_url() {
   match=$1; shift
@@ -28,6 +32,18 @@ case $KERNEL in
     ;;
 esac
 
+sh_c='sh -c'
+if [ "$CURRENT_USER" != 'root' ]; then
+  if command_exists sudo; then
+    sh_c='sudo -E sh -c'
+  elif command_exists su; then
+    sh_c='su -c'
+  else
+    output "Error: this installer needs the ability to run commands as root. We are unable to find either "sudo" or "su" available to make this happen."
+    exit 1
+  fi
+fi
+
 TMP=$(mktemp -d "${TMPDIR:-/tmp}/ctop.XXXXX")
 cd ${TMP}
 
@@ -55,6 +71,6 @@ wget -q --show-progress $url
 
 output "installing to /usr/local/bin"
 chmod +x ctop-*
-sudo mv ctop-* /usr/local/bin/ctop
+$sh_c "mv ctop-* /usr/local/bin/ctop"
 
 output "done!"