treewide: use perl.withPackages when possible

Since 03eaa48 added perl.withPackages, there is a canonical way to create a perl interpreter from a list of libraries, for use in script shebangs or generic build inputs. This method is declarative (what we are doing is clear), produces short shebangs[1] and needs not to wrap existing scripts. Unfortunately there are a few exceptions that I've found: 1. Scripts that are calling perl with the -T switch. This makes perl ignore PERL5LIB, which is what perl.withPackages is using to inform the interpreter of the library paths. 2. Perl packages that depends on libraries in their own path. This is not possible because perl.withPackages works at build time. The workaround is to add `-I $out/${perl.libPrefix}` to the shebang. In all other cases I propose to switch to perl.withPackages. [1]: https://lwn.net/Articles/779997/
2021-02-24 20:53:45 +01:00 · 2021-02-24 20:53:45 +01:00 · 61b7cab481
parent 3966039910
commit 61b7cab481
23 changed files with 73 additions and 123 deletions
--- a/nixos/modules/config/users-groups.nix
+++ b/nixos/modules/config/users-groups.nix
@ -556,10 +556,8 @@ in {
        install -m 0700 -d /root
        install -m 0755 -d /home

-        ${pkgs.perl}/bin/perl -w \
-          -I${pkgs.perlPackages.FileSlurp}/${pkgs.perl.libPrefix} \
-          -I${pkgs.perlPackages.JSON}/${pkgs.perl.libPrefix} \
-          ${./update-users-groups.pl} ${spec}
+        ${pkgs.perl.withPackages (p: [ p.FileSlurp p.JSON ])}/bin/perl \
+        -w ${./update-users-groups.pl} ${spec}
      '';

    # for backwards compatibility
--- a/nixos/modules/installer/tools/tools.nix
+++ b/nixos/modules/installer/tools/tools.nix
@ -34,7 +34,7 @@ let
    name = "nixos-generate-config";
    src = ./nixos-generate-config.pl;
    path = lib.optionals (lib.elem "btrfs" config.boot.supportedFilesystems) [ pkgs.btrfs-progs ];
-    perl = "${pkgs.perl}/bin/perl -I${pkgs.perlPackages.FileSlurp}/${pkgs.perl.libPrefix}";
+    perl = "${pkgs.perl.withPackages (p: [ p.FileSlurp ])}/bin/perl";
    inherit (config.system.nixos-generate-config) configuration desktopConfiguration;
    xserverEnabled = config.services.xserver.enable;
  };
--- a/nixos/modules/programs/command-not-found/command-not-found.nix
+++ b/nixos/modules/programs/command-not-found/command-not-found.nix
@ -14,10 +14,8 @@ let
    dir = "bin";
    src = ./command-not-found.pl;
    isExecutable = true;
-    inherit (pkgs) perl;
    inherit (cfg) dbPath;
-    perlFlags = concatStrings (map (path: "-I ${path}/${pkgs.perl.libPrefix} ")
-      [ pkgs.perlPackages.DBI pkgs.perlPackages.DBDSQLite pkgs.perlPackages.StringShellQuote ]);
+    perl = pkgs.perl.withPackages (p: [ p.DBDSQLite p.StringShellQuote ]);
  };

 in
--- a/nixos/modules/programs/command-not-found/command-not-found.pl
+++ b/nixos/modules/programs/command-not-found/command-not-found.pl
@ -1,4 +1,4 @@
-#! @perl@/bin/perl -w @perlFlags@
+#! @perl@/bin/perl -w

 use strict;
 use DBI;
--- a/nixos/modules/system/activation/switch-to-configuration.pl
+++ b/nixos/modules/system/activation/switch-to-configuration.pl
@ -1,4 +1,4 @@
-#! @perl@
+#! @perl@/bin/perl

 use strict;
 use warnings;
--- a/nixos/modules/system/activation/top-level.nix
+++ b/nixos/modules/system/activation/top-level.nix
@ -113,8 +113,7 @@ let
    configurationName = config.boot.loader.grub.configurationName;

    # Needed by switch-to-configuration.
-
-    perl = "${pkgs.perl}/bin/perl " + (concatMapStringsSep " " (lib: "-I${lib}/${pkgs.perl.libPrefix}") (with pkgs.perlPackages; [ FileSlurp NetDBus XMLParser XMLTwig ]));
+    perl = pkgs.perl.withPackages (p: with p; [ FileSlurp NetDBus XMLParser XMLTwig ]);
  };

  # Handle assertions and warnings
--- a/nixos/modules/system/boot/loader/grub/grub.nix
+++ b/nixos/modules/system/boot/loader/grub/grub.nix
@ -728,13 +728,17 @@ in
            utillinux = pkgs.util-linux;
            btrfsprogs = pkgs.btrfs-progs;
          };
+          perl = pkgs.perl.withPackages (p: with p; [
+            FileSlurp FileCopyRecursive
+            XMLLibXML XMLSAX XMLSAXBase
+            ListCompare JSON
+          ]);
        in pkgs.writeScript "install-grub.sh" (''
        #!${pkgs.runtimeShell}
        set -e
-        export PERL5LIB=${with pkgs.perlPackages; makePerlPath [ FileSlurp FileCopyRecursive XMLLibXML XMLSAX XMLSAXBase ListCompare JSON ]}
        ${optionalString cfg.enableCryptodisk "export GRUB_ENABLE_CRYPTODISK=y"}
      '' + flip concatMapStrings cfg.mirroredBoots (args: ''
-        ${pkgs.perl}/bin/perl ${install-grub-pl} ${grubConfig args} $@
+        ${perl}/bin/perl ${install-grub-pl} ${grubConfig args} $@
      '') + cfg.extraInstallCommands);

      system.build.grub = grub;
--- a/nixos/modules/system/etc/etc.nix
+++ b/nixos/modules/system/etc/etc.nix
@ -154,7 +154,7 @@ in
      ''
        # Set up the statically computed bits of /etc.
        echo "setting up /etc..."
-        ${pkgs.perl}/bin/perl -I${pkgs.perlPackages.FileSlurp}/${pkgs.perl.libPrefix} ${./setup-etc.pl} ${etc}/etc
+        ${pkgs.perl.withPackages (p: [ p.FileSlurp ])}/bin/perl ${./setup-etc.pl} ${etc}/etc
      '';

  };
--- a/nixos/modules/testing/service-runner.nix
+++ b/nixos/modules/testing/service-runner.nix
@ -6,7 +6,7 @@ let

  makeScript = name: service: pkgs.writeScript "${name}-runner"
    ''
-      #! ${pkgs.perl}/bin/perl -w -I${pkgs.perlPackages.FileSlurp}/${pkgs.perl.libPrefix}
+      #! ${pkgs.perl.withPackages (p: [ p.FileSlurp ])}/bin/perl -w

      use File::Slurp;

--- a/pkgs/applications/graphics/feh/default.nix
+++ b/pkgs/applications/graphics/feh/default.nix
@ -1,6 +1,6 @@
 { lib, stdenv, fetchurl, makeWrapper
 , xorg, imlib2, libjpeg, libpng
-, curl, libexif, jpegexiforient, perlPackages
+, curl, libexif, jpegexiforient, perl
 , enableAutoreload ? !stdenv.hostPlatform.isDarwin }:

 with lib;
@ -31,14 +31,7 @@ stdenv.mkDerivation rec {
                               --add-flags '--theme=feh'
  '';

-  checkInputs = [ perlPackages.perl perlPackages.TestCommand ];
-  preCheck = ''
-    export PERL5LIB="${perlPackages.TestCommand}/${perlPackages.perl.libPrefix}"
-  '';
-  postCheck = ''
-    unset PERL5LIB
-  '';
-
+  checkInputs = lib.singleton (perl.withPackages (p: [ p.TestCommand ]));
  doCheck = true;

  meta = {
--- a/pkgs/build-support/writers/default.nix
+++ b/pkgs/build-support/writers/default.nix
@ -257,18 +257,9 @@ rec {
  #     print "Howdy!\n" if true;
  #   ''
  writePerl = name: { libraries ? [] }:
-  let
-    perl-env = pkgs.buildEnv {
-      name = "perl-environment";
-      paths = libraries;
-      pathsToLink = [
-        "/${pkgs.perl.libPrefix}"
-      ];
-    };
-  in
-  makeScriptWriter {
-    interpreter = "${pkgs.perl}/bin/perl -I ${perl-env}/${pkgs.perl.libPrefix}";
-  } name;
+    makeScriptWriter {
+      interpreter = "${pkgs.perl.withPackages (p: libraries)}/bin/perl";
+    } name;

  # writePerlBin takes the same arguments as writePerl but outputs a directory (like writeScriptBin)
  writePerlBin = name:
--- a/pkgs/development/tools/misc/icon-naming-utils/default.nix
+++ b/pkgs/development/tools/misc/icon-naming-utils/default.nix
@ -1,4 +1,4 @@
-{lib, stdenv, fetchurl, perlPackages, librsvg}:
+{lib, stdenv, fetchurl, perl, librsvg}:

 stdenv.mkDerivation rec {
  name = "icon-naming-utils-0.8.90";
@ -8,14 +8,7 @@ stdenv.mkDerivation rec {
    sha256 = "071fj2jm5kydlz02ic5sylhmw6h2p3cgrm3gwdfabinqkqcv4jh4";
  };

-  buildInputs = [ librsvg ] ++ (with perlPackages; [ perl XMLSimple ]);
-
-  postInstall =
-    ''
-      # Add XML::Simple to the runtime search path.
-      substituteInPlace $out/libexec/icon-name-mapping \
-          --replace '/bin/perl' '/bin/perl -I${perlPackages.XMLSimple}/${perlPackages.perl.libPrefix}'
-    '';
+  buildInputs = [ librsvg (perl.withPackages (p: [ p.XMLSimple ])) ];

  meta = with lib; {
    homepage = "http://tango.freedesktop.org/Standard_Icon_Naming_Specification";
--- a/pkgs/misc/screensavers/xscreensaver/default.nix
+++ b/pkgs/misc/screensavers/xscreensaver/default.nix
@ -1,4 +1,4 @@
-{ lib, stdenv, fetchurl, pkg-config, bc, perl, perlPackages, pam, libXext, libXScrnSaver, libX11
+{ lib, stdenv, fetchurl, pkg-config, bc, perl, pam, libXext, libXScrnSaver, libX11
 , libXrandr, libXmu, libXxf86vm, libXrender, libXxf86misc, libjpeg, libGLU, libGL, gtk2
 , libxml2, libglade, intltool, xorg, makeWrapper, gle, gdk-pixbuf, gdk-pixbuf-xlib
 , forceInstallAllHacks ? false
@ -38,11 +38,13 @@ stdenv.mkDerivation rec {
  postInstall = ''
      wrapProgram $out/bin/xscreensaver-text \
        --prefix PATH : ${lib.makeBinPath [xorg.appres]}
-      wrapProgram $out/bin/xscreensaver-getimage-file \
-        --set PERL5LIB "$out/${perlPackages.perl.libPrefix}:${with perlPackages; makePerlPath [
-              EncodeLocale HTTPDate HTTPMessage IOSocketSSL LWP LWPProtocolHttps
-              MozillaCA NetHTTP NetSSLeay TryTiny URI
-              ]}"
+
+      substituteInPlace $out/bin/xscreensaver-getimage-file \
+        --replace '${perl}' '${perl.withPackages (p: with p;
+          [ EncodeLocale HTTPDate HTTPMessage IOSocketSSL
+            LWP LWPProtocolHttps MozillaCA NetHTTP
+            NetSSLeay TryTiny URI
+          ])}'
  ''
  + lib.optionalString forceInstallAllHacks ''
    make -C hacks/glx dnalogo
--- a/pkgs/os-specific/linux/apparmor/default.nix
+++ b/pkgs/os-specific/linux/apparmor/default.nix
@ -136,10 +136,9 @@ let
        wrapProgram $out/bin/$prog --prefix PYTHONPATH : "$out/lib/${python.libPrefix}/site-packages:$PYTHONPATH"
      done

-      substituteInPlace $out/bin/aa-notify --replace /usr/bin/notify-send ${libnotify}/bin/notify-send
-      # aa-notify checks its name and does not work named ".aa-notify-wrapped"
-      mv $out/bin/aa-notify $out/bin/aa-notify-wrapped
-      makeWrapper ${perl}/bin/perl $out/bin/aa-notify --set PERL5LIB ${libapparmor}/${perl.libPrefix} --add-flags $out/bin/aa-notify-wrapped
+      substituteInPlace $out/bin/aa-notify \
+        --replace /usr/bin/notify-send ${libnotify}/bin/notify-send \
+        --replace /usr/bin/perl "${perl}/bin/perl -I ${libapparmor}/${perl.libPrefix}"
    '';

    inherit doCheck;
--- a/pkgs/os-specific/linux/rdma-core/default.nix
+++ b/pkgs/os-specific/linux/rdma-core/default.nix
@ -1,7 +1,6 @@
 { lib, stdenv, fetchFromGitHub, cmake, pkg-config, docutils
 , pandoc, ethtool, iproute, libnl, udev, python3, perl
-, makeWrapper
-} :
+}:

 let
  version = "34.0";
@ -17,7 +16,7 @@ in stdenv.mkDerivation {
    sha256 = "sha256-2HFtj595sDmWqAewIMwKMaiSDVVWKdQA9l0QsPcw8qA=";
  };

-  nativeBuildInputs = [ cmake pkg-config pandoc docutils makeWrapper ];
+  nativeBuildInputs = [ cmake pkg-config pandoc docutils ];
  buildInputs = [ libnl ethtool iproute udev python3 perl ];

  cmakeFlags = [
@ -39,7 +38,8 @@ in stdenv.mkDerivation {
  postFixup = ''
    for pls in $out/bin/{ibfindnodesusing.pl,ibidsverify.pl}; do
      echo "wrapping $pls"
-      wrapProgram $pls --prefix PERL5LIB : "$out/${perl.libPrefix}"
+      substituteInPlace $pls --replace \
+        "${perl}/bin/perl" "${perl}/bin/perl -I $out/${perl.libPrefix}"
    done
  '';

--- a/pkgs/tools/backup/store-backup/default.nix
+++ b/pkgs/tools/backup/store-backup/default.nix
@ -1,4 +1,4 @@
-{lib, stdenv, which, coreutils, perl, fetchurl, perlPackages, makeWrapper, diffutils , writeScriptBin, bzip2}:
+{lib, stdenv, which, coreutils, perl, fetchurl, makeWrapper, diffutils , writeScriptBin, bzip2}:

 # quick usage:
 # storeBackup.pl --sourceDir /home/user --backupDir /tmp/my_backup_destination
@ -37,12 +37,10 @@ stdenv.mkDerivation rec {
    find $out -name "*.pl" | xargs sed -i \
      -e 's@/bin/pwd@${coreutils}/bin/pwd@' \
      -e 's@/bin/sync@${coreutils}/bin/sync@' \
-      -e '1 s@/usr/bin/env perl@${perl}/bin/perl@'
+      -e '1 s@/usr/bin/env perl@${perl.withPackages (p: [ p.DBFile ])}/bin/perl@'

    for p in $out/bin/*
-      do wrapProgram "$p" \
-      --prefix PERL5LIB ":" "${perlPackages.DBFile}/${perlPackages.perl.libPrefix}" \
-      --prefix PATH ":" "${lib.makeBinPath [ which bzip2 ]}"
+      do wrapProgram "$p" --prefix PATH ":" "${lib.makeBinPath [ which bzip2 ]}"
    done

    patchShebangs $out
--- a/pkgs/tools/backup/znapzend/default.nix
+++ b/pkgs/tools/backup/znapzend/default.nix
@ -21,6 +21,11 @@ let
    propagatedBuildInputs = [ perlPackages.IOPipely Mojolicious-8-35 ];
  };

+  perl' = perl.withPackages (p:
+    [ MojoIOLoopForkCall-0-20
+      p.TAPParserSourceHandlerpgTAP
+    ]);
+
  version = "0.20.0";
  checksum = "15lb5qwksa508m9bj6d3n4rrjpakfaas9qxspg408bcqfp7pqjw3";
 in
@ -35,7 +40,7 @@ stdenv.mkDerivation {
    sha256 = checksum;
  };

-  buildInputs = [ wget perl MojoIOLoopForkCall-0-20 perlPackages.TAPParserSourceHandlerpgTAP ];
+  buildInputs = [ wget perl' ];

  nativeBuildInputs = [ autoconf automake autoreconfHook ];

@ -53,30 +58,6 @@ stdenv.mkDerivation {
    automake
  '';

-  postInstall = ''
-    substituteInPlace $out/bin/znapzend --replace "${perl}/bin/perl" \
-      "${perl}/bin/perl \
-      -I${Mojolicious-8-35}/${perl.libPrefix} \
-      -I${perlPackages.TAPParserSourceHandlerpgTAP}/${perl.libPrefix} \
-      -I${MojoIOLoopForkCall-0-20}/${perl.libPrefix} \
-      -I${perlPackages.IOPipely}/${perl.libPrefix} \
-      "
-    substituteInPlace $out/bin/znapzendzetup --replace "${perl}/bin/perl" \
-      "${perl}/bin/perl \
-      -I${Mojolicious-8-35}/${perl.libPrefix} \
-      -I${perlPackages.TAPParserSourceHandlerpgTAP}/${perl.libPrefix} \
-      -I${MojoIOLoopForkCall-0-20}/${perl.libPrefix} \
-      -I${perlPackages.IOPipely}/${perl.libPrefix} \
-      "
-    substituteInPlace $out/bin/znapzendztatz --replace "${perl}/bin/perl" \
-      "${perl}/bin/perl \
-      -I${Mojolicious-8-35}/${perl.libPrefix} \
-      -I${perlPackages.TAPParserSourceHandlerpgTAP}/${perl.libPrefix} \
-      -I${MojoIOLoopForkCall-0-20}/${perl.libPrefix} \
-      -I${perlPackages.IOPipely}/${perl.libPrefix} \
-      "
-  '';
-
  meta = with lib; {
    description = "High performance open source ZFS backup with mbuffer and ssh support";
    homepage    = "http://www.znapzend.org";
--- a/pkgs/tools/filesystems/file-rename/default.nix
+++ b/pkgs/tools/filesystems/file-rename/default.nix
@ -1,4 +1,4 @@
-{ lib, stdenv, fetchurl, perlPackages, makeWrapper }:
+{ lib, stdenv, fetchurl, perl, perlPackages }:

 perlPackages.buildPerlPackage {
  pname = "File-Rename";
@ -9,17 +9,15 @@ perlPackages.buildPerlPackage {
    sha256 = "1cf6xx2hiy1xalp35fh8g73j67r0w0g66jpcbc6971x9jbm7bvjy";
  };

-  nativeBuildInputs = [ makeWrapper ];
-
  # Fix an incorrect platform test that misidentifies Darwin as Windows
  postPatch = ''
    substituteInPlace Makefile.PL \
      --replace '/win/i' '/MSWin32/'
  '';

-  postInstall = ''
-    wrapProgram $out/bin/rename \
-      --prefix PERL5LIB : $out/${perlPackages.perl.libPrefix}
+  postFixup = ''
+    substituteInPlace $out/bin/rename \
+      --replace "#!${perl}/bin/perl" "#!${perl}/bin/perl -I $out/${perl.libPrefix}"
  '';

  doCheck = !stdenv.isDarwin;
--- a/pkgs/tools/misc/lbdb/default.nix
+++ b/pkgs/tools/misc/lbdb/default.nix
@ -1,4 +1,4 @@
-{ lib, stdenv, fetchurl, fetchpatch, perl, perlPackages, finger_bsd, makeWrapper
+{ lib, stdenv, fetchurl, fetchpatch, perl, finger_bsd
 , abook ? null
 , gnupg ? null
 , goobook ? null
@ -8,9 +8,8 @@

 let
  version = "0.48.1";
+  perl' = perl.withPackages (p: with p; [ ConvertASN1 perlldap AuthenSASL ]);
 in
-with lib;
-with perlPackages;
 stdenv.mkDerivation {
  pname = "lbdb";
  inherit version;
@ -19,20 +18,20 @@ stdenv.mkDerivation {
    sha256 = "1gr5l2fr9qbdccga8bhsrpvz6jxigvfkdxrln9wyf2xpps5cdjxh";
  };

-  nativeBuildInputs = [ makeWrapper ];
-  buildInputs = [ goobook perl ConvertASN1 perlldap AuthenSASL ]
-    ++ optional (!stdenv.isDarwin) finger_bsd
-    ++ optional   (abook != null) abook
-    ++ optional   (gnupg != null) gnupg
-    ++ optional (goobook != null) goobook
-    ++ optional   (khard != null) khard
-    ++ optional      (mu != null) mu;
+  buildInputs = [ goobook perl' ]
+    ++ lib.optional (!stdenv.isDarwin) finger_bsd
+    ++ lib.optional   (abook != null) abook
+    ++ lib.optional   (gnupg != null) gnupg
+    ++ lib.optional (goobook != null) goobook
+    ++ lib.optional   (khard != null) khard
+    ++ lib.optional      (mu != null) mu;
+
  configureFlags = [ ]
-    ++ optional   (abook != null) "--with-abook"
-    ++ optional   (gnupg != null) "--with-gpg"
-    ++ optional (goobook != null) "--with-goobook"
-    ++ optional   (khard != null) "--with-khard"
-    ++ optional      (mu != null) "--with-mu";
+    ++ lib.optional   (abook != null) "--with-abook"
+    ++ lib.optional   (gnupg != null) "--with-gpg"
+    ++ lib.optional (goobook != null) "--with-goobook"
+    ++ lib.optional   (khard != null) "--with-khard"
+    ++ lib.optional      (mu != null) "--with-mu";

  patches = [ ./add-methods-to-rc.patch
    # fix undefined exec_prefix. Remove with the next release
@ -42,12 +41,8 @@ stdenv.mkDerivation {
      excludes = [ "debian/changelog" ];
    })
  ];
-  postFixup = "wrapProgram $out/lib/mutt_ldap_query --prefix PERL5LIB : "
-    + "${AuthenSASL}/${perl.libPrefix}"
-    + ":${ConvertASN1}/${perl.libPrefix}"
-    + ":${perlldap}/${perl.libPrefix}";

-  meta = {
+  meta = with lib; {
    homepage = "https://www.spinnaker.de/lbdb/";
    license = licenses.gpl2;
    platforms = platforms.all;
--- a/pkgs/tools/networking/tgt/default.nix
+++ b/pkgs/tools/networking/tgt/default.nix
@ -1,4 +1,4 @@
-{ stdenv, lib, fetchFromGitHub, libxslt, libaio, systemd, perl, perlPackages
+{ stdenv, lib, fetchFromGitHub, libxslt, libaio, systemd, perl
 , docbook_xsl, coreutils, lsof, rdma-core, makeWrapper, sg3_utils, util-linux
 }:

@ -35,7 +35,7 @@ stdenv.mkDerivation rec {

  postInstall = ''
    substituteInPlace $out/sbin/tgt-admin \
-      --replace "#!/usr/bin/perl" "#! ${perl}/bin/perl -I${perlPackages.ConfigGeneral}/${perl.libPrefix}"
+      --replace "#!/usr/bin/perl" "#! ${perl.withPackages (p: [ p.ConfigGeneral ])}/bin/perl"
    wrapProgram $out/sbin/tgt-admin --prefix PATH : \
      ${lib.makeBinPath [ lsof sg3_utils (placeholder "out") ]}

--- a/pkgs/tools/package-management/dpkg/default.nix
+++ b/pkgs/tools/package-management/dpkg/default.nix
@ -56,7 +56,8 @@ stdenv.mkDerivation rec {
    ''
      for i in $out/bin/*; do
        if head -n 1 $i | grep -q perl; then
-          wrapProgram $i --prefix PERL5LIB : $out/${perl.libPrefix}
+          substituteInPlace $i --replace \
+            "${perl}/bin/perl" "${perl}/bin/perl -I $out/${perl.libPrefix}"
        fi
      done

--- a/pkgs/tools/virtualization/nixos-container/default.nix
+++ b/pkgs/tools/virtualization/nixos-container/default.nix
@ -1,11 +1,11 @@
-{ substituteAll, perlPackages, shadow, util-linux }:
+{ substituteAll, perl, shadow, util-linux }:

 substituteAll {
    name = "nixos-container";
    dir = "bin";
    isExecutable = true;
    src = ./nixos-container.pl;
-    perl = "${perlPackages.perl}/bin/perl -I${perlPackages.FileSlurp}/${perlPackages.perl.libPrefix}";
+    perl = perl.withPackages (p: [ p.FileSlurp ]);
    su = "${shadow.su}/bin/su";
    utillinux = util-linux;

--- a/pkgs/tools/virtualization/nixos-container/nixos-container.pl
+++ b/pkgs/tools/virtualization/nixos-container/nixos-container.pl
@ -1,4 +1,4 @@
-#! @perl@
+#! @perl@/bin/perl

 use strict;
 use POSIX;