stargazing/notwa-util/dedupe

#!/usr/bin/env sh

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

: \
 && 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)" \
 && { [ $# -eq 0 ] || sha256sum >"$t" "$@" ;} \
 && find ! -type d -exec sha256sum {} + >>"$t~" \
 && sort -k2, <"$t~" >>"$t" \
 && awk -v D="$D" -v h="$h" -F'  ' "$program" <"$t" \
;