From ee67afd21ccecbc29f72e763def7dafe6229b31b Mon Sep 17 00:00:00 2001
From: Andrew Cady <d@cryptonomic.net>
Date: Sat, 9 Oct 2021 17:19:51 -0400
Subject: improve/shorten help output

---
 cryptonomic-vpn | 67 +++++++++++++++++++++------------------------------------
 1 file changed, 25 insertions(+), 42 deletions(-)

diff --git a/cryptonomic-vpn b/cryptonomic-vpn
index bdb8f41..68669da 100755
--- a/cryptonomic-vpn
+++ b/cryptonomic-vpn
@@ -8,58 +8,36 @@ help()
     prefix0="       $0 "
     prefix1=${prefix0//?/ }
     cat <<EOF
-
-Synopsis:
-
-$prefix0 <hostname>
-
-$prefix0 --remote-ip <IP address> \\
-$prefix1 --remote-name <hostname>
-
-
 Usage:
 
-$prefix0 --remote-ip <IP address> \\
-$prefix1 --remote-name <hostname> \\
+$prefix0 [--remote-name] <hostname>
+
+$prefix0 --remote-name <hostname> \\
+$prefix1 --remote-ip <IP address> \\
 $prefix1 [--remote-key-type rsa]  \\
 $prefix1 [--local-key <filename>]
 
-
 Options:
 
-    --remote-name
-
-        Specify the name that we give to the remote side.
-
-        Remote name is mandatory, except that if a single non-option argument is
-        given, then it is treated as if it were the argument to --remote-name.
+    --remote-name       Specify the name that we give to the remote side.
 
-    --remote-ip
+                        Remote name is mandatory, except that if a single
+                        non-option argument is given, then it is treated as if
+                        it were the argument to --remote-name.
 
-        The IP specifies an IP to connect to.
+    --remote-ip         The address of the VPN gateway.
 
-        The name specifies a name we give to the remote side.
+                        If not specified, the hostname specified with the
+                        --remote-name option will be resolved to obtain an IP.
 
-        If not specified, the hostname specified with the --remote-name option
-        will be resolved to obtain the IP.
+    --remote-key-type   The type of key to request from the remote IP via the SSH
+                        protocol. If specified, it must be 'rsa'.
 
-    --remote-key-type
+    --local-key         The location of the private key file.
 
-        The remote key will be fetched via the SSH protocol on port 22 on the
-        remote IP. This option specifies which server key type to request from
-        the server.
-
-        If specified, it must be 'rsa'.
-
-    --local-key
-
-        This specifies the location of the private key file.
-
-        The filename is considered relative to /etc/ssh if it has no slashes.
-
-        The default is 'ssh_host_rsa_key'.
-
-        The key must be an RSA key.
+                        The filename is considered relative to /etc/ssh if it
+                        has no slashes. The default is 'ssh_host_rsa_key'. It
+                        must be an RSA key.
 
 EOF
 }
@@ -87,6 +65,11 @@ parse_options()
                -- "$@")
     eval set -- "$OPTS"
     unset OPTS
+    if [ $# = 0 ]
+    then
+        help
+        exit
+    fi
 
     while true
     do
@@ -106,7 +89,7 @@ parse_options()
     if [ $# = 1 -a -z "$REMOTE_NAME" ]
     then
         REMOTE_NAME=$1
-    elif [ $# != 0 ]
+    elif [ $# != 0 -o -z "$REMOTE_NAME" ]
     then
         help
         exit 1
@@ -151,7 +134,7 @@ validate_local_key()
         */*) ;;
         *) LOCAL_KEY=/etc/ssh/$LOCAL_KEY ;;
     esac
-    [ -f "$LOCAL_KEY" -a -r "$LOCAL_KEY" ] || die "local key ($LOCAL_KEY)"
+    [ -f "$LOCAL_KEY" -a -r "$LOCAL_KEY" ] || die "could not read local key (filename=$LOCAL_KEY)"
 }
 
 main()
@@ -159,8 +142,8 @@ main()
     parse_options "$@"
 
     # The validation functions modify the values to normalize them.
+    validate_remote_name     || die 'invalid remote name'
     validate_remote_ip       || die 'invalid remote ip'
-    validate_remote_name     || die "invalid remote name '$REMOTE_NAME'"
     validate_remote_key_type || die 'invalid remote key type'
     validate_local_key       || die 'invalid local key'
 
-- 
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