Use WSL ssh-agent by default

utils/bin/start

@@ -1,18 +1,20 @@
 #!/bin/sh
-usage () {
+usage() {
   echo "usage: $0 [-w] [-h]"
-  echo "   -w   use the WSL ssh-agent instead of OpenSSH for Windows"
+  echo "   -w   use OpenSSH for Windows instead of WSL ssh-agent"
   echo "   -h   show help and exit"
 }
 
-require() {
-  if ! command -v "$@" >/dev/null 2>&1; then
-    >&2 echo "ERROR: required command not found: $1"
-    exit 1
-  fi
+error() {
+  printf "ERROR: %s\n" "$1" >&2
+  exit 1
 }
 
-start_with_wsl_agent() {
+require() {
+  command -v "$@" >/dev/null 2>&1 || error "'$1' not found"
+}
+
+start_wsl_agent() {
   if [ "$#" -gt 0 ]; then
     SHLVL=0 exec ssh-agent "$SHELL" -c "$@"
   else
@@ -20,15 +22,18 @@ start_with_wsl_agent() {
   fi
 }
 
-start_with_windows_agent() {
+start_windows_agent() {
   require socat
   require npiperelay
 
   # Forward SSH Agent requests from withitn WSL to OpenSSH for Windows, based on:
   # https://stuartleeks.com/posts/wsl-ssh-key-forward-to-windows/
-  export SSH_AUTH_SOCK=$HOME/.ssh/agent.sock
+  export SSH_AUTH_SOCK="$HOME/.ssh/agent.sock"
   [ -S "$SSH_AUTH_SOCK" ] && rm "$SSH_AUTH_SOCK"
-  socat UNIX-LISTEN:$SSH_AUTH_SOCK,fork EXEC:"npiperelay -ei -s //./pipe/openssh-ssh-agent",nofork &
+  socat \
+    UNIX-LISTEN:$SSH_AUTH_SOCK,fork \
+    EXEC:"npiperelay -ei -s //./pipe/openssh-ssh-agent",nofork \
+    &
 
   if [ "$#" -gt 0 ]; then
     SHLVL=0 exec "$SHELL" -c "$@"
@@ -37,32 +42,23 @@ start_with_windows_agent() {
   fi
 }
 
-# Use OpenSSH for Windows by default.
-WSL_SSH_AGENT=false
+main() {
+  WSL_SSH_AGENT=yes
+  while getopts ":wh" arg; do
+    case "$arg" in
+      w)  WSL_SSH_AGENT=no;;
+      h)  usage; exit 0;;
+      ?)  usage >&2; error "unknown option -$OPTARG";;
+    esac
+    shift
+  done
 
-while getopts ":wh" arg; do
-  case "$arg" in
-    w)
-      WSL_SSH_AGENT=true
-      ;;
+  if [ "$WSL_SSH_AGENT" = "yes" ]; then
+    start_wsl_agent "$@"
+  else
+    start_windows_agent "$@"
+  fi
+}
 
-    h)
-      usage
-      exit 0
-      ;;
-
-    ?)
-      >&2 echo "ERROR: unknown option -$OPTARG"
-      >&2 usage
-      exit 1
-      ;;
-  esac
-  shift
-done
-
-if [ "$WSL_SSH_AGENT" = true ]; then
-  start_with_wsl_agent "$@"
-else
-  start_with_windows_agent "$@"
-fi
+main "$@"