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+# SAML IdP Probe
+
+Probe a SAML IdP deployment
+
+## Installation
+
+Download the dependent [Bash Library](https://github.internet2.edu/InCommon/bash-library) source, change directory to the source directory, and install the source into ``/tmp`` as follows:
+
+```Shell
+$ export BIN_DIR=/tmp/bin
+$ export LIB_DIR=/tmp/lib
+$ ./install.sh $BIN_DIR $LIB_DIR
+```
+
+or install into your home directory:
+
+```Shell
+$ export BIN_DIR=$HOME/bin
+$ export LIB_DIR=$HOME/lib
+$ ./install.sh $BIN_DIR $LIB_DIR
+```
+
+A target directory will be created if one doesn't already exist. The following files will be installed:
+
+```Shell
+$ ls -1 $BIN_DIR
+cget.sh
+
+$ ls -1 $LIB_DIR 
+command_paths.sh
+compatible_date.sh
+compatible_mktemp.sh
+extract_entity.xsl
+http_tools.sh
+md_tools.sh
+```
+
+Next download the SAML IdP Probe project source, change directory to the source directory, and install the source on top of the previous installation:
+
+```Shell
+$ ./install.sh $BIN_DIR $LIB_DIR
+```
+
+The following files will be installed:
+
+```Shell
+$ ls -1 $BIN_DIR
+cget.sh
+check_idp_error_urls.sh
+list_local_idp_error_urls.sh
+
+
+$ ls -1 $LIB_DIR 
+command_paths.sh
+compatible_date.sh
+compatible_mktemp.sh
+extract_IdP_entityIDs.xsl
+extract_IdP_names.xsl
+extract_InCommon_IdP_entityIDs.xsl
+extract_entity.xsl
+http_tools.sh
+md_tools.sh
+```
+
+## Overview
+
+Given a list of entityIDs and a metadata source, bash script ``check_idp_error_urls.sh`` probes each entity and determines which of the entityIDs correspond to SAML IdP deployments. For each such deployment, the script determines whether it has an ``errorURL`` in metadata and whether or not that URL is resolvable. For example:
+
+```Shell
+# Fetch the main production metadata aggregate at md.incommon.org:
+$ MD_LOCATION=http://md.incommon.org/InCommon/InCommon-metadata.xml
+$ MD_PATH=$MD_DIR/InCommon-metadata.xml
+$ /usr/bin/curl --silent $MD_LOCATION > $MD_PATH
+
+# Probe every errorURL in IdP metadata registered by InCommon
+$ /bin/cat $MD_PATH \
+  | /usr/bin/xsltproc $LIB_DIR/extract_InCommon_IdP_entityIDs.xsl - \
+  | $BIN_DIR/check_idp_error_urls.sh -f $MD_PATH
+```
+
+See the inline help file for details:
+
+```Shell
+$ $BIN_DIR/check_idp_error_urls.sh -h
+```
+
+## Compatibility
+
+The bash scripts are compatible with both GNU/Linux and Mac OS. The XSLT scripts are written in XSLT 1.0.
+
+## Dependencies
+
+* [Bash Library](https://github.internet2.edu/InCommon/bash-library)