A simple tool for resigning an iOS app ipa with a new certificate/mobileprovision

resign.sh

#!/usr/bin/env bash 

if [[ ! ( # any of the following are not true
        # 1st arg is an existing regular file
        -f "$1" &&
        # ...and it has a .ipa extension
        "${1##*.}" == "ipa" &&
        # 2nd arg is an existing regular file
        -f "$2" &&
        # ...and it has an .mobileprovision extension
        "${2##*.}" == "mobileprovision" &&
        # 3rd arg is a non-empty string
        -n "$3"
        ) ]];
    then
    echo '    Usage: resign.sh Application.ipa foo/bar.mobileprovision "iPhone Distribution: I can haz code signed"'
    exit;
fi

## Exit on use of an uninitialized variable
set -o nounset
## Exit if any statement returns a non-true return value (non-zero)
set -o errexit
## Announce commands
#set -o xtrace

realpath(){
    echo "$(cd "$(dirname "$1")"; echo -n "$(pwd)/$(basename "$1")")";
}

TMP="$(mktemp -d -t ./resign)"
IPA="$(realpath $1)"
IPA_NEW="$(pwd)/$(basename $IPA .ipa).resigned.ipa"
PROVISION="$(realpath $2)"
CERTIFICATE="$3"
CLEANUP_TEMP=0 # Do not remove this line or "set -o nounset" will error on checks below
#CLEANUP_TEMP=1 # Uncomment this line if you want this script to clean up after itself
cd "$TMP"
[[ $CLEANUP_TEMP -ne 1 ]] && echo "Using temp dir: $TMP"
unzip -q "$IPA"
echo App has AppID $(/usr/libexec/PlistBuddy -c 'Print :CFBundleIdentifier' Payload/*.app/Info.plist)
security cms -D -i Payload/AtlantaJournal.app/embedded.mobileprovision > mobileprovision.plist
echo "Trying to resign with '$(/usr/libexec/PlistBuddy -c "Print :Name" mobileprovision.plist)', which supports '$(/usr/libexec/PlistBuddy -c "Print :Entitlements:application-identifier" mobileprovision.plist)'"
rm -rf Payload/*.app/_CodeSignature Payload/*.app/CodeResources
cp "$PROVISION" Payload/*.app/embedded.mobileprovision
/usr/bin/codesign -f -s "$CERTIFICATE" --resource-rules Payload/*.app/ResourceRules.plist Payload/*.app
zip -qr "$IPA_NEW" Payload
[[ $CLEANUP_TEMP -eq 1 ]] && rm -rf "$TMP"

How the certificate is provided as input ? is it the path till the file ?