From cc5f3535c23585c76821cc00133e14810da9995d Mon Sep 17 00:00:00 2001
From: Andrew Cady <d@jerkface.net>
Date: Sat, 9 Jan 2021 14:42:00 -0500
Subject: bup: backup files or snapshots

---
 dot/local/bin/bup | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 dot/local/bin/bup

diff --git a/dot/local/bin/bup b/dot/local/bin/bup
new file mode 100644
index 0000000..11c3a21
--- /dev/null
+++ b/dot/local/bin/bup
@@ -0,0 +1,53 @@
+#!/bin/sh
+
+# TODO: rbup makes remote backup
+
+btrfs_subvolume_backup()
+{
+    TARGET=$1~$(date -r "$1" -I) || return
+    [ ! -e "$TARGET" ] || TARGET=$1~$(date -r "$1" -Im)
+    [ ! -e "$TARGET" ] || TARGET=$1~$(date -r "$1" -Is)
+    [ ! -e "$TARGET" ] || return
+
+    btrfs subvolume snapshot -r "$1" "$TARGET"
+}
+
+file_with_extension_backup()
+{
+    local basename extension stamp date_format
+    date_format=%F_%H%M%S
+    basename=${1%.*}
+    extension=${1##*.}
+    stamp=$(date -r "$1" +"$date_format") || return
+
+    TARGET=$basename.$stamp.$extension
+    if [ ! -e "$TARGET" ]
+    then
+       cp --reflink=auto -T "$1" "$TARGET"
+    else
+        printf 'Warning: No backup was made, since an apparent backup exists here: "%s"\n' "$TARGET" >&2
+        return 0
+    fi
+}
+
+set -e
+
+[ $# = 1 ]
+if [ -d "$1" ]
+then
+    if btrfs subvolume show "$1"
+    then
+        btrfs_subvolume_backup "$1"
+        exit
+    fi
+elif [ -f "$1" ]
+then
+    case "$1" in
+        *.*) file_with_extension_backup "$1"
+             exit
+        ;;
+    esac
+fi
+
+echo 'Unimplemented' >&2
+exit 1
-- 
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