New git utility script

[skip ci]

mk/linux/mg_git.sh

@@ -0,0 +1,43 @@
+#!/bin/bash
+
+usage() {
+
+  echo
+  echo 'Usage:'
+  echo "$(basename $0)"' <COMMAND>'
+  echo
+  echo 'COMMAND is a standard git command, e.g. "pull" to run "git pull"'
+
+}
+
+case $1 in 
+
+  pull ) 
+    echo '==> Running "git '"$1"'" on main repository...'
+    cd $(dirname $0)
+    git $1
+    if [ $? -ne 0 ]; then
+      echo 'Error: Failed to run "git '"$1"'" on main repository.' >&2
+      exit 2
+    fi
+    echo
+    echo '==> Running "git '"$1"'" on submodules...'
+    git submodule foreach git $1
+    if [ $? -ne 0 ]; then
+      echo 'Error: Failed to run "git '"$1"'" on submodules.' >&2
+      exit 2
+    fi
+  ;;
+
+  '' )
+    echo 'Error: No command was provided.'"$1" >&2
+    usage
+    exit 1
+  ;;
+
+  * )
+    echo 'Error: Unknown command: '"$1" >&2
+    exit 1
+  ;;
+
+esac