From 02bedd712a19dab976b12d5f98b5e92f2a8b969f Mon Sep 17 00:00:00 2001
From: Tim Byrne <sultan@locehilios.com>
Date: Mon, 27 Jan 2020 07:31:58 -0600
Subject: [PATCH] Add example of parsing YADM_HOOK_FULL_COMMAND

---
 .../parsing_full_command_example/README.md    |  7 +++++
 .../parsing_full_command_example/pre_log      | 26 +++++++++++++++++++
 2 files changed, 33 insertions(+)
 create mode 100644 contrib/hooks/parsing_full_command_example/README.md
 create mode 100755 contrib/hooks/parsing_full_command_example/pre_log

diff --git a/contrib/hooks/parsing_full_command_example/README.md b/contrib/hooks/parsing_full_command_example/README.md
new file mode 100644
index 0000000..3593a5e
--- /dev/null
+++ b/contrib/hooks/parsing_full_command_example/README.md
@@ -0,0 +1,7 @@
+## Example of parsing `$YADM_HOOK_FULL_COMMAND`
+
+Contributed by Tim Byrne
+
+Hook    | Description
+----    | -----------
+pre_log | Provides an example of parsing `$YADM_HOOK_FULL_COMMAND` in Bash
diff --git a/contrib/hooks/parsing_full_command_example/pre_log b/contrib/hooks/parsing_full_command_example/pre_log
new file mode 100755
index 0000000..0af52f3
--- /dev/null
+++ b/contrib/hooks/parsing_full_command_example/pre_log
@@ -0,0 +1,26 @@
+#!/bin/bash
+
+# yadm exposes all parameters of the command which triggers a hook. Those
+# parameters are exported as the environment variable YADM_HOOK_FULL_COMMAND.
+# Any spaces, tabs, or backslashes in those parameters are escaped with a
+# backslash. The function `parse_full_command()` is a demonstration of parsing
+# those values which may be escaped.
+
+function parse_full_command() {
+  local delim=$'\x1e' # ASCII Record Separator
+  local space=$'\x1f' # ASCII Unit Separator
+  local tab=$'\t'     # ASCII TAB
+  local cmd
+  cmd="$YADM_HOOK_FULL_COMMAND"
+  cmd="${cmd//\\ /$space}"      # swap escaped spaces for `1f`
+  cmd="${cmd//\\\\/\\}"         # fix escaped backslashes
+  cmd="${cmd//\\$tab/$tab}"     # fix escaped tabs
+  cmd="${cmd// /$delim}"        # convert space delimiters to `1c`
+  cmd="${cmd//$space/ }"        # convert `1f` back to spaces
+  # parse data into an array
+  IFS=$delim read -r -a full_cmd <<< "$cmd"
+}
+parse_full_command
+for param in "${full_cmd[@]}"; do
+  echo "Parameter: '$param'"
+done