feat(net): add option -x to unshare network

try

@@ -233,7 +233,11 @@ EOF
     # --pid: create a new process namespace (needed fr procfs to work right)
     # --fork: necessary if we do --pid
     #         "Creation of a persistent PID namespace will fail if the --fork option is not also specified."
-    unshare --mount --map-root-user --user --pid --fork "$mount_and_execute"
+    if [ "$EXTRA_NS" = "net" ]; then
+        unshare --mount --map-root-user --user --pid --fork --net "$mount_and_execute"
+    else
+        unshare --mount --map-root-user --user --pid --fork "$mount_and_execute"
+    fi
     TRY_EXIT_STATUS=$?
 
     ################################################################################
@@ -476,10 +480,11 @@ error() {
 
 usage() {
     cat >&2 <<EOF
-Usage: $TRY_COMMAND [-nvhy] [-i PATTERN] [-D DIR] [-U PATH] CMD [ARG ...]
+Usage: $TRY_COMMAND [-nvhyx] [-i PATTERN] [-D DIR] [-U PATH] CMD [ARG ...]
 
   -n                don't commit or prompt for commit (overrides -y)
   -y                assume yes to all prompts (overrides -n)
+  -x                unshare the network namespace
   -i PATTERN        ignore paths that match PATTERN on summary and commit
   -D DIR            work in DIR (implies -n)
   -U PATH           path to unionfs helper (e.g., mergerfs, unionfs-fuse)
@@ -508,7 +513,7 @@ NO_COMMIT="interactive"
 # Includes all patterns given using the `-i` flag; will be used with `grep -f`
 IGNORE_FILE="$(mktemp)"
 
-while getopts ":yvnhi:D:U:" opt
+while getopts ":yvnhxi:D:U:" opt
 do
     case "$opt" in
         (y)   NO_COMMIT="commit";;
@@ -528,6 +533,7 @@ do
               fi
               UNION_HELPER="$OPTARG"
               export UNION_HELPER;;
+        (x)   EXTRA_NS="net";;
         (h|*) usage
               exit 0;;
     esac