passwordless ssh scp login (host-based authentication)

I made this script for automatiс adding of public key to remote server for passwordless login (host-based authentication).

It also
- creates public key locally, if not yet generated;
- checks if public host is already there, and don't make a dup.

Must be executed on client side! It will copy public key to the server and concatenate with the authorized_keys file.

#!/bin/ksh

RUSER=someuser
VSA=someserver.com
L="$RUSER@$VSA"

OPTS="-o StrictHostKeyChecking=no"  #-v

if [ ! -e ~/.ssh/id_rsa.pub ]; then
 echo "========= Generating public key, with empty passpharase..."
 ssh-keygen -q -f ~/.ssh/id_rsa -t rsa

 #client permissions
 chmod 700 ~/.ssh
 chmod go-rwx ~/.ssh/*
fi

echo "========= Copy pubkey for the $L..."
scp $OPTS ~/.ssh/id_rsa.pub $L: 2>/dev/null
if [ $? == "0" ]; then
 echo "Done."
fi

echo "========= Setup the public key for $L and permissions there..."
ssh $OPTS $L '
 if [ ! -e ~/.ssh ]; then  mkdir ~/.ssh; chmod 700 ~/.ssh;  fi;
 cd ~/.ssh;
 grep -q -s `head -1 ~/id_rsa.pub | cut -d " " -f 2` authorized_keys;
 if [ $? != 0 ]; then  cat ~/id_rsa.pub >> authorized_keys; echo "Key added";
  else  echo "Key was already there";  fi;
 chmod 600 authorized_keys;
 rm ~/id_rsa.pub
 ' 2>/dev/null

Enter empty passphrase when asked during ssh key generation.

Tested on AIX, but should run perfect (ksh) on other systems without modifications.