add-ssh-keys.sh

#!/bin/bash
#
# add ssh keys

PROG=${0##*/}

KEY_DIR=~/.ssh
PUB_SFX='.pub'

# on non-MacOS systems, comment this line out
USE_KEYCHAIN_OPTION='-K'

usage() {
  cat 1>&2 <<EOF
usage: $PROG [options] [KEYNAME] ..

Add one or more keys from files within $KEY_DIR with filenames containing the
string KEYNAME.  If no KEYNAME given, load all keys from files that have
corresponding files with the suffix ".pub".

On MacOS, uses '-K' to cause ssh passwords to be retained in the system keychain
(which survives reboots, which is awesome).

Options:
  -h    show this help
  -n    don't do anything, but show what would have been done
  -l    list all available key files
  -v    be verbose
EOF
}

talk()   { echo   1>&2 "$*" ; }
talkf()  { printf 1>&2 "$@" ; }
vtalk()  { (( verbose )) && talk  "$*" ; }
vtalkf() { (( verbose )) && talkf "$@" ; }

all_key_files() {
  local name pub_name
  cd $KEY_DIR
  for pub_name in `ls -1 *.pub` ; do
    name=`basename $pub_name $PUB_SFX`
    if [[ -f "$name"  && ! -L "$name" ]]; then
      echo "$name"
    fi
  done
}

list_keys() {
  if (( $# > 0 )); then
    printf 1>&2 "%d keys found:\n" $#
    local keyname
    for keyname in "${all_keys[@]}"; do
      talk "  $keyname"
    done
  else
    talk "No keys found in $KEY_DIR"
  fi
  talk ''
  if [[ -n "$current_ids" ]]; then
    talk "SSH Agent currently knows about these keys:"
    ssh-add -l
  else
    talk "SSH Agent knows nothing about any keys"
  fi
}

norun= verbose= list_keys=

while getopts 'hnvl' opt ; do
  case "$opt" in
    h) usage ;;
    n) norun=1 ;;
    v) verbose=1 ;;
    l) list_keys=1 ;;
  esac
done
shift $(( OPTIND - 1 ))

all_keys=( `all_key_files` )
vtalk "Found ${#all_keys[@]} key files"

current_ids="`ssh-add -l`"
if (( verbose )); then
  talk "Found $( ssh-add -l | wc -l ) keys with ssh-agent"
fi

(( list_keys )) && { list_keys "${all_keys[@]}" ; exit ; }

if (( $# > 0 )); then
  all_keys=( "$@" )
fi

for keyname in "${all_keys[@]}" ; do
  vtalkf "Checking key: $keyname : "
  if [[ ! "$current_ids" =~ $keyname ]] ; then
    keyfile="$KEY_DIR/$keyname"
    if [[ -e "$keyfile" ]]; then
      vtalk " found"
      ( set -x ; ssh-add $USE_KEYCHAIN_OPTION $keyfile )
    else
      talk "no such file"
    fi
  elif (( verbose )) ; then
    talk " already installed"
  fi
done