diff --git a/notwa-util/dedupe b/notwa-util/dedupe
index 62da551..9d58899 100755
--- a/notwa-util/dedupe
+++ b/notwa-util/dedupe
@@ -1,16 +1,41 @@
 #!/usr/bin/env sh
 
+# Copyright (C) 2022 Connor Olding
+
+usage='dedupe [OPTION...] {SOURCE} {TARGET} [FILE...]
+Copy files, recursively, from the source directory to the target directory,
+creating hard (or soft) links to any earlier file containing the same data.
+Optional file arguments allow for finer control of the order of files seen.
+
+      --help                 display this help and exit
+      --soft                 create soft links (default)
+      --hard                 create hard links
+
+This software is provided WITHOUT WARRANTY under the terms of the ISC license.
+'
+
 read -r program <<'EOF'
 BEGIN{if(!D){print U;exit 64}E=(Q="'")"\"'\""Q;H=(G=".")(F="/");I=" -- "Q;J="[^/]*/";sub(F"?$",F,D)gsub(Q,E,D)}function C(x){if(X=system(x))exit X}{if((p=$2)==B){print V;exit 65}for(r=z=i=d=B;d!=!i;i++){b=a=p;d=sub("/.*",B,a);sub(J,B,p);if(a==G G)e=!sub(J,B,z);else z=a==G?z:b!=a?z a F:z a;if(e||!i&&!a){print W;exit 65}}P=p=!z?H:z;if((o=O[$1])==p)next;gsub(Q,E,P);M=m=D P;gsub("/[^/]+$",B,M);if(!u[M]++)C("mkdir -p"I M Q);if(o){T=split(o,t,F);S=split(p,s,F);for(i=1;t[i]==s[i];i++);for(j=i;j<S;j++)r=r G H;for(j=i;j<T;j++)r=r t[j]F;r=h?o:r t[T];gsub(Q,E,r);C("ln"(h?I D:" -s"I)r"' '"m Q);next}O[$1]=p;C("cp -i"I P"' '"m Q)}
 EOF
 
+h=0
+
 : \
- && complain() { printf '\033[1m%s\033[m: %s\n' >&2 dedupe "$*" ;} \
- && { [ -d /tmp ] || { complain "/tmp must be mounted"; exit 72 ;} ;} \
- && h=0 && { [ "$1" != --hard ] || shift && h=1 ;} \
- && cd "$1" && shift && D="$1" && shift && t="$(mktemp)" \
+ && die() { printf '\033[1mdedupe:\033[m %s\n' >&2 "$2"; exit "$1" ;} \
+ && while o="${1#-}" && [ "${#o}" != "${#1}" ] && shift \
+    ;do case "$o" in \
+        (-) break ;; \
+        (-help) printf '\033[1mUsage:\033[m %s' "$usage"; exit ;; \
+        (-soft) h=0 ;; \
+        (-hard) h=1 ;; \
+        (-*) die 64 "unknown long option: -$o" ;; \
+        (*) die 64 "unknown short option: -${o%"${o#?}"}" ;; \
+    esac;done \
+ && { [ -d /tmp ] || die 72 "/tmp must be mounted" ;} \
+ && { [ $# -ge 2 ] || die 64 'expected at least 2 arguments' ;} \
+ && cd -- "$1" && shift && D="$1" && shift && t="$(mktemp)" \
  && { [ $# -eq 0 ] || sha256sum >"$t" "$@" ;} \
- && find ! -type d -exec sha256sum {} + >>"$t~" \
+ && find ! -type d ! -type s -exec sha256sum -- {} + >>"$t~" \
  && sort -k2, <"$t~" >>"$t" \
  && awk -v D="$D" -v h="$h" -F'  ' "$program" <"$t" \
 ;