diff --git a/nixos/module/hectic/service/sentinèlla.nix b/nixos/module/hectic/service/sentinèlla.nix
new file mode 100644
index 0000000..ee3e387
--- /dev/null
+++ b/nixos/module/hectic/service/sentinèlla.nix
@@ -0,0 +1,106 @@
+{ 
+  inputs,
+  flake,
+  self,
+}:
+{ 
+  pkgs,
+  lib,
+  config,
+  ...
+}: let
+  system = pkgs.system;
+  cfg = config.hectic.services.server-health;
+  #   URLS="http://..."     # default: none
+  #   VOLUMES="/ /home"     # default: all from df -P
+in {
+  options = {
+    hectic.services."sentinèlla" = {
+      probe = {
+        enable   = lib.mkEnableOption "enable sentinèlla probe services, that provides endpoints for server status check";
+        urls = lib.mkOption {
+          type = lib.types.port;
+          description = ''
+            urls to check
+          '';
+        };
+        volumes = lib.mkOption {
+          type = lib.types.port;
+          description = ''
+            volumes to check
+          '';
+        };
+        port = lib.mkOption {
+          type = lib.types.port;
+          description = ''
+            service's port
+          '';
+        };
+        environmentPath = lib.mkOption {
+          type = lib.types.path;
+	  example = ''
+            config.sops.secrets."name-of-service/environment".path
+	  '';
+	  description = ''
+	    in case when you do not want show configurations in repository
+	    ```
+              VOLUMES=
+              URLS=
+              PORT=
+	    ```
+	  '';
+        };
+      };
+      sentinel = {
+        enable   = lib.mkEnableOption "enable sentinèlla sentinel services, that reported servers statuses based on probe polls";
+        environmentPath = lib.mkOption {
+          type = lib.types.path;
+	  example = ''
+            config.sops.secrets."name-of-service/environment".path
+	  '';
+	  description = ''
+	    in case when you do not want show configurations in repository
+	  '';
+        };
+      };
+    };
+  };
+  config = lib.mkMerge [
+    (lib.mkIf cfg.probe.enable {
+      services.nginx.virtualHosts = {
+      };
+      systemd.services."sentinèlla-probe" = {
+        description = "Hectic server health check";
+        after = [ "network.target" ];
+        wantedBy = [ "multi-user.target" ];
+        serviceConfig = {
+          Type = "simple";
+          ExecStart = "${self.packages.${system}.server-health}/bin/probe";
+          EnvironmentFile = cfg.probe.environmentPath;
+          Environment = (if cfg.probe.urls != null then [
+            "URLS=${cfg.probe.urls}"
+          ] else []) ++ (if cfg.probe.volumes != null then [
+            "VOLUMES=${cfg.volumes}"
+          ] else []) ++ (if cfg.probe.port != null then [
+            "PORT=${builtins.toString cfg.probe.port}"
+          ] else []);
+          Restart = "always";
+          RestartSec = "5s";
+          
+          # Shutdown configuration
+          TimeoutStopSec = "30s";
+          KillSignal = "SIGTERM";
+          KillMode = "mixed";
+          
+          # Security and process management
+          RemainAfterExit = false;
+          StandardOutput = "journal";
+          StandardError = "journal";
+        };
+      };
+    })
+    (lib.mkIf cfg.sentinel.enable {
+      
+    })
+  ];
+}
diff --git a/nixos/module/hectic/service/server-health.nix b/nixos/module/hectic/service/server-health.nix
deleted file mode 100644
index 626ecf7..0000000
--- a/nixos/module/hectic/service/server-health.nix
+++ /dev/null
@@ -1,71 +0,0 @@
-{ 
-  inputs,
-  flake,
-  self,
-}:
-{ 
-  pkgs,
-  lib,
-  config,
-  ...
-}: let
-  system = pkgs.system;
-  cfg = config.hectic.services.server-health;
-  #   URLS="http://..."     # default: none
-  #   VOLUMES="/ /home"     # default: all from df -P
-in {
-  options = {
-    hectic.services.server-health = {
-      enable   = lib.mkEnableOption "enable serverhelth services";
-      urls = lib.mkOption {
-        type = lib.types.port;
-        default = "5899";
-        description = ''
-	  urls to check
-        '';
-      };
-      volumes = lib.mkOption {
-        type = lib.types.port;
-        default = "5899";
-        description = ''
-          volumes to check
-        '';
-      };
-      port = lib.mkOption {
-        type = lib.types.port;
-        default = "5899";
-        description = ''
-          service's port
-        '';
-      };
-    };
-  };
-  config = lib.mkIf cfg.enable {
-    systemd.services."hectic-server-health" = {
-      description = "Hectic server health check";
-      after = [ "network.target" ];
-      wantedBy = [ "multi-user.target" ];
-      serviceConfig = {
-        Type = "simple";
-        ExecStart = "${self.packages.${system}.server-health}/bin/server-health";
-        Environment = (if cfg.urls != null then [
-	  "URLS=${cfg.urls}"
-	] else []) ++ (if cfg.volumes != null then [
-	  "VOLUMES=${cfg.volumes}"
-	] else []);
-        Restart = "always";
-        RestartSec = "5s";
-        
-        # Shutdown configuration
-        TimeoutStopSec = "30s";
-        KillSignal = "SIGTERM";
-        KillMode = "mixed";
-        
-        # Security and process management
-        RemainAfterExit = false;
-        StandardOutput = "journal";
-        StandardError = "journal";
-      };
-    };
-  };
-}
diff --git a/package/default.nix b/package/default.nix
index 1417b59..2d69e77 100644
--- a/package/default.nix
+++ b/package/default.nix
@@ -238,42 +238,42 @@ in {
       sha256 = "sha256-atKhccp8Pr8anJUo+M9hnYkYrcgnB9SxrpmsiVusJZs=";
     };
   };
-  nvim-alias = pkgs.callPackage ./nvim-alias.nix {};
-  bolt-unpack = pkgs.callPackage ./bolt-unpack.nix {};
-  nvim-pager = pkgs.callPackage ./nvim-pager.nix {};
-  printobstacle = pkgs.callPackage ./printobstacle.nix {};
-  printprogress = pkgs.callPackage ./printprogress.nix {};
-  colorize = pkgs.callPackage ./colorize.nix {};
-  github-gh-tl = pkgs.callPackage ./github/gh-tl.nix {};
-  supabase-with-env-collection = pkgs.callPackage ./supabase-with-env-collection.nix {};
-  migration-name = pkgs.callPackage ./migration-name.nix {};
-  prettify-log = pkgs.callPackage ./prettify-log/default.nix rust.commonArgs;
-  pg-from = pkgs.callPackage ./postgres/pg-from/default.nix rust.commonArgs;
-  pg-schema = pkgs.callPackage ./postgres/pg-schema/default.nix rust.commonArgs;
-  pg_wdumpall = pkgs.callPackage ./postgres/pg_wdumpall.nix rust.commonArgs; 
-  pg_wdump = pkgs.callPackage ./postgres/pg_wdump.nix rust.commonArgs; 
-  pg-migration = pkgs.callPackage ./postgres/pg-migration/default.nix rust.commonArgs;
-  pg-17-ext-hemar = buildHemarExt pkgs "17";
-  pg-17-ext-http = buildHttpExt pkgs "17";
-  pg-17-ext-smtp-client = buildSmtpExt pkgs "17";
-  pg-17-ext-plhaskell = buildPlHaskellExt pkgs "17";
-  pg-17-ext-plsh = buildPlShExt pkgs "17";
-  pg-16-ext-hemar = buildHemarExt pkgs "16";
-  pg-16-ext-http = buildHttpExt pkgs "16";
-  pg-16-ext-smtp-client = buildSmtpExt pkgs "16";
-  pg-16-ext-plhaskell = buildPlHaskellExt pkgs "16";
-  pg-16-ext-plsh = buildPlShExt pkgs "16";
-  pg-15-ext-hemar = buildHemarExt pkgs "15";
-  pg-15-ext-http = buildHttpExt pkgs "15";
-  pg-15-ext-smtp-client = buildSmtpExt pkgs "15";
-  pg-15-ext-plhaskell = buildPlHaskellExt pkgs "15";
-  pg-15-ext-plsh = buildPlShExt pkgs "15";
-  slpt = pkgs.callPackage ./slpt.nix {};
-  c-hectic = pkgs.callPackage ./c/hectic/default.nix {};
-  watch = pkgs.callPackage ./c/watch/default.nix {};
-  support-bot = pkgs.callPackage ./support-bot {};
-  nix-derivation-hash = pkgs.callPackage ./nix-derivation-hash {};
-  server-health = pkgs.callPackage ./server-health {};
-  shellplot = pkgs.callPackage ./shellplot {};
-  sops = pkgs.callPackage ./sops.nix {};
+  nvim-alias                   = pkgs.callPackage ./nvim-alias.nix                    {};
+  bolt-unpack                  = pkgs.callPackage ./bolt-unpack.nix                   {};
+  nvim-pager                   = pkgs.callPackage ./nvim-pager.nix                    {};
+  printobstacle                = pkgs.callPackage ./printobstacle.nix                 {};
+  printprogress                = pkgs.callPackage ./printprogress.nix                 {};
+  colorize                     = pkgs.callPackage ./colorize.nix                      {};
+  github-gh-tl                 = pkgs.callPackage ./github/gh-tl.nix                  {};
+  supabase-with-env-collection = pkgs.callPackage ./supabase-with-env-collection.nix  {};
+  migration-name               = pkgs.callPackage ./migration-name.nix                {};
+  prettify-log                 = pkgs.callPackage ./prettify-log/default.nix          rust.commonArgs;
+  pg-from                      = pkgs.callPackage ./postgres/pg-from/default.nix      rust.commonArgs;
+  pg-schema                    = pkgs.callPackage ./postgres/pg-schema/default.nix    rust.commonArgs;
+  pg_wdumpall                  = pkgs.callPackage ./postgres/pg_wdumpall.nix          rust.commonArgs; 
+  pg_wdump                     = pkgs.callPackage ./postgres/pg_wdump.nix             rust.commonArgs; 
+  pg-migration                 = pkgs.callPackage ./postgres/pg-migration/default.nix rust.commonArgs;
+  slpt                         = pkgs.callPackage ./slpt.nix                          {};
+  c-hectic                     = pkgs.callPackage ./c/hectic/default.nix              {};
+  watch                        = pkgs.callPackage ./c/watch/default.nix               {};
+  support-bot                  = pkgs.callPackage ./support-bot                       {};
+  nix-derivation-hash          = pkgs.callPackage ./nix-derivation-hash               {};
+  "sentinèlla"                 = pkgs.callPackage (./. + "/sentinèlla")               {};
+  shellplot                    = pkgs.callPackage ./shellplot                         {};
+  sops                         = pkgs.callPackage ./sops.nix                          {};
+  pg-17-ext-hemar              = buildHemarExt     pkgs "17";
+  pg-17-ext-http               = buildHttpExt      pkgs "17";
+  pg-17-ext-smtp-client        = buildSmtpExt      pkgs "17";
+  pg-17-ext-plhaskell          = buildPlHaskellExt pkgs "17";
+  pg-17-ext-plsh               = buildPlShExt      pkgs "17";
+  pg-16-ext-hemar              = buildHemarExt     pkgs "16";
+  pg-16-ext-http               = buildHttpExt      pkgs "16";
+  pg-16-ext-smtp-client        = buildSmtpExt      pkgs "16";
+  pg-16-ext-plhaskell          = buildPlHaskellExt pkgs "16";
+  pg-16-ext-plsh               = buildPlShExt      pkgs "16";
+  pg-15-ext-hemar              = buildHemarExt     pkgs "15";
+  pg-15-ext-http               = buildHttpExt      pkgs "15";
+  pg-15-ext-smtp-client        = buildSmtpExt      pkgs "15";
+  pg-15-ext-plhaskell          = buildPlHaskellExt pkgs "15";
+  pg-15-ext-plsh               = buildPlShExt      pkgs "15";
 }
diff --git a/package/sentinèlla/default.nix b/package/sentinèlla/default.nix
new file mode 100644
index 0000000..c1efaaa
--- /dev/null
+++ b/package/sentinèlla/default.nix
@@ -0,0 +1,10 @@
+{ writeShellScriptBin, socat, dash }:
+writeShellScriptBin "server-health" ''
+  set +a
+  LOOP_FILE=${./probe-loop.sh}
+  socat() { ${socat}/bin/socat $@ }
+  dash()  { ${dash}/bin/dash   $@ }
+  set -a
+
+  ${dash}/bin/dash ${./probe.sh}
+''
diff --git a/package/sentinèlla/probe-loop.sh b/package/sentinèlla/probe-loop.sh
new file mode 100644
index 0000000..7e25f9f
--- /dev/null
+++ b/package/sentinèlla/probe-loop.sh
@@ -0,0 +1,185 @@
+#!/bin/dash
+
+# router.sh — POSIX sh HTTP backend (for socat)
+# usage: socat -T5 -t5 TCP-LISTEN:${port},reuseaddr,fork EXEC:"sh ${currentfile}"
+# Routes:
+#   GET /status  -> check $URLS (0/0 if unset)
+#   GET /disk    -> check $VOLUMES (all if unset)
+# Env:
+#   URLS="http://..."     # default: none
+#   VOLUMES="/ /home"     # default: all from df -P
+#   TIMEOUT=5
+
+base64() {
+  local mod
+  mod="${1:?}"
+  
+  case "$mod" in
+    encode) 
+      printf '%s' "${2:?}" | od -An -t u1 | tr -s ' ' | tr -d '\n' | awk '
+        BEGIN {
+          A="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
+        }
+        function dec2bin(n,    r,len,pad) {
+            if (n==0) return "00000000"
+            while (n>0) {
+                r = (n%2) r
+                n = int(n/2)
+            }
+            return sprintf("%08s", r)
+        }
+        function bin2dec(s,    i,d,r) {
+            r=0
+            for(i=1;i<=length(s);i++) {
+                d=substr(s,i,1)
+                r = r*2 + d
+            }
+            return r
+        }
+        function buildbin(t,    r) {
+          for(i=1;i<=NF;i+=1) {
+            #printf("%s | %s\n", dec2bin($i), $i)
+            r = sprintf("%s%s", r, dec2bin($i))
+          }
+          return r
+        }
+        function base64(b,    r,c) {
+          for(i=1;i<=length(b);i+=6) {
+            #printf("%s | %s\n", substr(b,i,6), bin2dec(substr(b,i,6)))
+            c = substr(A, bin2dec(substr(b,i,6))+1, 1)
+            r = sprintf("%s%s", r, c)
+          }
+          return r
+        }
+        {  
+          b=buildbin($1)
+          l=length(b)
+	  lack = (6 - l % 6) % 6
+          b = sprintf("%s%0*d", b, lack, 0)
+	  r = base64(b)
+	  print lack
+	  for(i=1;i<=lack/2;i+=1) {
+	    r = sprintf("%s=", r)
+          }
+          print r
+        }
+      '
+        ;;
+    decode) 
+      printf '%b\n' "$(printf '%s' "${2:?}" | awk ' BEGIN {
+          A="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
+        }
+        function dec2bin(n,    r,len,pad) {
+            if (n==0) return "000000"
+            while (n>0) {
+                r = (n%2) r
+                n = int(n/2)
+            }
+            r = sprintf("%6s", r)
+            gsub(/ /,"0",r)
+            return r
+        }
+        {
+          for(i=1;i<=length($1);i+=1) {
+	    b=sprintf("%s%s", b, dec2bin(index(A, substr($1,i,1))-1))
+          }
+          for(i=1; i<=length(b); i+=8){
+            n=0
+            for(j=0;j<8;j++) n = n*2 + (substr(b,i+j,1)=="1")
+            printf "\\x%02X", n
+          }
+        }
+      ')"
+        ;;
+  esac
+}
+
+TIMEOUT=${TIMEOUT:-5}
+[ -n "$VOLUMES" ] || VOLUMES=$(df -P | awk 'NR>1{print $6}')
+
+route_status() {
+    if [ -z "$URLS" ]; then
+        printf '{\n  "checks": [],\n  "summary":{"total":0,"ok":0}\n}\n'
+        return
+    fi
+    {
+        printf '{\n  "checks": [\n'
+        first=1 okcnt=0 tot=0
+        for u in $URLS; do
+            tot=$((tot+1))
+            res=$(curl -sS -m "$TIMEOUT" -o /dev/null -w '%{http_code} %{time_total}' "$u" 2>/dev/null) || res="000 0"
+            code=${res%% *}; ttot=${res#* }
+            case $code in 2*|3*) ok=true; okcnt=$((okcnt+1));; *) ok=false;; esac
+            [ $first -eq 0 ] && printf ',\n'; first=0
+            printf '    {"url":"%s","code":%s,"time_s":%s,"ok":%s}' "$u" "$code" "$ttot" "$ok"
+        done
+        printf '\n  ],\n  "summary":{"total":%s,"ok":%s}\n}\n' "$tot" "$okcnt"
+    }
+}
+
+route_disk() {
+    {
+        printf '{\n  "volumes": [\n'
+        first=1
+        for v in $VOLUMES; do
+	    # POSIX df -P: Filesystem 1K-blocks Used Available Capacity Mounted on
+	    # shellcheck disable=SC2046
+            set -- $(df -P "$v" 2>/dev/null | awk 'NR==2{print $2, $3, $4, $5, $6}')
+            size=$1 used=$2 avail=$3 usep=$4 mnt=$5
+            [ -z "$size" ] && continue
+            [ $first -eq 0 ] && printf ',\n'; first=0
+            printf '    {"mount":"%s","size_blocks":%s,"used":%s,"avail":%s,"use_percent":"%s"}' \
+              "$mnt" "$size" "$used" "$avail" "$usep"
+        done
+        printf '\n  ]\n}\n'
+    }
+}
+
+require_auth=false
+[ -n "$USER" ] && [ -n "$PASS" ] && require_auth=true
+
+# --- read request & headers ---
+IFS= read -r req || exit 0
+cr=$(printf '\r')
+while IFS= read -r line; do
+  [ -z "$line" ] && break
+  [ "$line" = "$cr" ] && break
+  case "$line" in
+    "Authorization: Basic "*) 
+        tok=${line#Authorization: Basic }
+        tok=$(printf '%s' "$tok" | tr -d '\r\n')
+        expect=$(base64 encode "$USER:$PASS")
+        [ "$tok" = "$expect" ] && auth_ok=true
+        ;;
+  esac
+done
+
+# --- auth gate ---
+unauth() {
+  body='{"error":"unauthorized"}'
+  len=$(printf '%s' "$body" | wc -c | awk '{print $1}')
+  printf 'HTTP/1.1 401 Unauthorized\r\n'
+  printf 'Content-Type: application/json\r\n'
+  printf 'Content-Length: %s\r\n' "$len"
+  printf 'WWW-Authenticate: Basic realm="minimal", charset="UTF-8"\r\n'
+  printf 'Connection: close\r\n\r\n'
+  printf '%s' "$body"
+}
+
+if $require_auth && ! $auth_ok; then
+  unauth
+  exit 0
+fi
+
+tmp=$(mktemp) || exit 1
+trap 'rm -f "$tmp"' EXIT INT HUP
+
+case "$req" in
+  "GET /status "*) route_status >"$tmp"; status='200 OK'; ctype='application/json' ;;
+  "GET /disk "*)   route_disk   >"$tmp"; status='200 OK'; ctype='application/json' ;;
+  *)               printf 'Not found\n' >"$tmp"; status='404 Not Found'; ctype='text/plain' ;;
+esac
+
+len=$(wc -c <"$tmp" | awk '{print $1}')
+printf 'HTTP/1.1 %s\r\nContent-Type: %s\r\nContent-Length: %s\r\nConnection: close\r\n\r\n' "$status" "$ctype" "$len"
+cat "$tmp"
diff --git a/package/sentinèlla/probe.sh b/package/sentinèlla/probe.sh
new file mode 100644
index 0000000..fdaae2d
--- /dev/null
+++ b/package/sentinèlla/probe.sh
@@ -0,0 +1,3 @@
+#!/bin/dash
+
+socat -T5 -t5 TCP-LISTEN:"${PORT:-5988}",reuseaddr,fork EXEC:"dash $LOOP_FILE"
diff --git a/package/sentinèlla/sentinel.sh b/package/sentinèlla/sentinel.sh
new file mode 100644
index 0000000..5619f5a
--- /dev/null
+++ b/package/sentinèlla/sentinel.sh
@@ -0,0 +1,3 @@
+#!/bin/dash
+
+
diff --git a/package/server-health/default.nix b/package/server-health/default.nix
deleted file mode 100644
index 58134ad..0000000
--- a/package/server-health/default.nix
+++ /dev/null
@@ -1,4 +0,0 @@
-{ writeShellScriptBin, socat, bash }:
-writeShellScriptBin "server-health" ''
-  ${socat}/bin/socat -T5 -t5 TCP-LISTEN:''${PORT:-5988},reuseaddr,fork EXEC:"${bash}/bin/sh ${./server-health.sh}"
-''
diff --git a/package/server-health/server-health.sh b/package/server-health/server-health.sh
deleted file mode 100644
index a6cb500..0000000
--- a/package/server-health/server-health.sh
+++ /dev/null
@@ -1,72 +0,0 @@
-#!/bin/sh
-# router.sh — POSIX sh HTTP backend (for socat)
-# usage: socat -T5 -t5 TCP-LISTEN:${port},reuseaddr,fork EXEC:"sh ${currentfile}"
-# Routes:
-#   GET /status  -> check $URLS (0/0 if unset)
-#   GET /disk    -> check $VOLUMES (all if unset)
-# Env:
-#   URLS="http://..."     # default: none
-#   VOLUMES="/ /home"     # default: all from df -P
-#   TIMEOUT=5
-
-TIMEOUT=${TIMEOUT:-5}
-[ -n "$VOLUMES" ] || VOLUMES=$(df -P | awk 'NR>1{print $6}')
-
-route_status() {
-    if [ -z "$URLS" ]; then
-        printf '{\n  "checks": [],\n  "summary":{"total":0,"ok":0}\n}\n'
-        return
-    fi
-    {
-        printf '{\n  "checks": [\n'
-        first=1 okcnt=0 tot=0
-        for u in $URLS; do
-            tot=$((tot+1))
-            res=$(curl -sS -m "$TIMEOUT" -o /dev/null -w '%{http_code} %{time_total}' "$u" 2>/dev/null) || res="000 0"
-            code=${res%% *}; ttot=${res#* }
-            case $code in 2*|3*) ok=true; okcnt=$((okcnt+1));; *) ok=false;; esac
-            [ $first -eq 0 ] && printf ',\n'; first=0
-            printf '    {"url":"%s","code":%s,"time_s":%s,"ok":%s}' "$u" "$code" "$ttot" "$ok"
-        done
-        printf '\n  ],\n  "summary":{"total":%s,"ok":%s}\n}\n' "$tot" "$okcnt"
-    }
-}
-
-route_disk() {
-    {
-        printf '{\n  "volumes": [\n'
-        first=1
-        for v in $VOLUMES; do
-	    # POSIX df -P: Filesystem 1K-blocks Used Available Capacity Mounted on
-	    # shellcheck disable=SC2046
-            set -- $(df -P "$v" 2>/dev/null | awk 'NR==2{print $2, $3, $4, $5, $6}')
-            size=$1 used=$2 avail=$3 usep=$4 mnt=$5
-            [ -z "$size" ] && continue
-            [ $first -eq 0 ] && printf ',\n'; first=0
-            printf '    {"mount":"%s","size_blocks":%s,"used":%s,"avail":%s,"use_percent":"%s"}' \
-              "$mnt" "$size" "$used" "$avail" "$usep"
-        done
-        printf '\n  ]\n}\n'
-    }
-}
-
-# --- read request & headers ---
-IFS= read -r req || exit 0
-cr=$(printf '\r')
-while IFS= read -r line; do
-  [ -z "$line" ] && break
-  [ "$line" = "$cr" ] && break
-done
-
-tmp=$(mktemp) || exit 1
-trap 'rm -f "$tmp"' EXIT INT HUP
-
-case "$req" in
-  "GET /status "*) route_status >"$tmp"; status='200 OK'; ctype='application/json' ;;
-  "GET /disk "*)   route_disk   >"$tmp"; status='200 OK'; ctype='application/json' ;;
-  *)               printf 'Not found\n' >"$tmp"; status='404 Not Found'; ctype='text/plain' ;;
-esac
-
-len=$(wc -c <"$tmp" | awk '{print $1}')
-printf 'HTTP/1.1 %s\r\nContent-Type: %s\r\nContent-Length: %s\r\nConnection: close\r\n\r\n' "$status" "$ctype" "$len"
-cat "$tmp"
diff --git a/package/shellplot/shellplot.sh b/package/shellplot/shellplot.sh
index 0fc52e4..c9ca6e9 100644
--- a/package/shellplot/shellplot.sh
+++ b/package/shellplot/shellplot.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/dash
 # ImageMagick: scatter plot "by dots" from (x y) data
 # - Input: points.txt with "x y" per line (whitespace-separated)
 # - Output: plot.png (white bg, black dots). Also draws an optional polyline through points.