ack installs, but reports "use: command not found"

[Calvin-L]

Issue description

The ack tool can be installed, but reports errors like "use: command not found". These errors are symptoms of trying to execute a Perl script with Bash; I am not sure why the shebang line in the ack script is not working.

(Also, unrelated: while nix-shell -p ack works, nix-env -i ack instead reports "error: selector 'ack' matches no derivations". Perhaps I have some misunderstanding about what the arguments to these commands mean.)

Steps to reproduce

$ nix-shell --pure -p ack
$ ack --help
/nix/store/q82s26mj9z0j29kcd2w31ykssd9nc67b-perl5.28.0-ack-2.24/bin/ack: line 3: use: command not found
/nix/store/q82s26mj9z0j29kcd2w31ykssd9nc67b-perl5.28.0-ack-2.24/bin/ack: line 4: use: command not found
/nix/store/q82s26mj9z0j29kcd2w31ykssd9nc67b-perl5.28.0-ack-2.24/bin/ack: line 5: our: command not found
/nix/store/q82s26mj9z0j29kcd2w31ykssd9nc67b-perl5.28.0-ack-2.24/bin/ack: line 7: use: command not found
/nix/store/q82s26mj9z0j29kcd2w31ykssd9nc67b-perl5.28.0-ack-2.24/bin/ack: line 8: syntax error near unexpected token `('
/nix/store/q82s26mj9z0j29kcd2w31ykssd9nc67b-perl5.28.0-ack-2.24/bin/ack: line 8: `use Getopt::Long 2.38 ();'

Shebang line

$ type ack
ack is /nix/store/q82s26mj9z0j29kcd2w31ykssd9nc67b-perl5.28.0-ack-2.24/bin/ack
$ head -n1 /nix/store/q82s26mj9z0j29kcd2w31ykssd9nc67b-perl5.28.0-ack-2.24/bin/ack
#!/nix/store/xhir85mv5mfwdkbisnx3bl9h6agjmix4-perl-5.28.0/bin/perl -I/nix/store/xhir85mv5mfwdkbisnx3bl9h6agjmix4-perl-5.28.0/lib/perl5/site_perl -I/nix/store/fm5qg2kljrks0m5jbba6f69ik4vad3bv-perl5.28.0-File-Next-1.16/lib/perl5/site_perl -I/nix/store/xhir85mv5mfwdkbisnx3bl9h6agjmix4-perl-5.28.0/lib/perl5/site_perl -I/nix/store/fm5qg2kljrks0m5jbba6f69ik4vad3bv-perl5.28.0-File-Next-1.16/lib/perl5/site_perl -I/nix/store/xhir85mv5mfwdkbisnx3bl9h6agjmix4-perl-5.28.0/lib/perl5/site_perl -I/nix/store/fm5qg2kljrks0m5jbba6f69ik4vad3bv-perl5.28.0-File-Next-1.16/lib/perl5/site_perl -I/nix/store/q82s26mj9z0j29kcd2w31ykssd9nc67b-perl5.28.0-ack-2.24/lib/perl5/site_perl

Technical details

• system: "x86_64-darwin"
• host os: Darwin 17.7.0, macOS 10.13.6
• multi-user?: no
• sandbox: no
• version: nix-env (Nix) 2.1.1
• channels(cloncari): "nixpkgs-19.03pre153206.f753852e11d"
• nixpkgs: /Users/cloncari/.nix-defexpr/channels/nixpkgs

[kliu128]

Seems to work for me on NixOS unstable.

[nix-shell:~/Documents/zero]$ ack --help                                                                                                                    
Usage: ack [OPTION]... PATTERN [FILES OR DIRECTORIES]                                                                                                       
                                                                                                                                                            
Search for PATTERN in each source file in the tree from the current                                                                                         
directory on down.  If any files or directories are specified, then                                                                                         
only those files and directories are checked.  ack may also search                                                                                          
STDIN, but only if no file or directory arguments are specified,                                                                                            
or if one of them is "-".                                                                                                                                   
                                                                                                                                                            
Default switches may be specified in ACK_OPTIONS environment variable or                                                                                    
an .ackrc file. If you want no dependency on the environment, turn it                                                                                       
off with --noenv.

• system: "x86_64-linux"
• host os: Linux 4.19.0-rc4, NixOS, 19.03.git.77f3f43 (Koi)
• multi-user?: yes
• sandbox: yes
• version: nix-env (Nix) 2.1.2
• channels(root): ""
• nixpkgs: /etc/nixos/nixpkgs

[dtzWill]

Same, Linux here as well though. Can any Darwin user give this a try?

I don't know OSX versions but I do recall some (presumably older-ish?) had some issue with shebang handling, but it'd probably be best to wait for someone who knows more before jumping to any conclusions :).

[lheckemann]

I had a similar problem the other day when I got a script for the wrong architecture — it turns out that when calling the interpreter specified in the shebang results in "Exec format error", (at least on linux) the kernel will try to run it with /bin/sh instead. @Calvin-L can you run /nix/store/xhir85mv5mfwdkbisnx3bl9h6agjmix4-perl-5.28.0/bin/perl?

[Calvin-L]

@lheckemann I can, in fact!

$ /nix/store/xhir85mv5mfwdkbisnx3bl9h6agjmix4-perl-5.28.0/bin/perl --version

This is perl 5, version 28, subversion 0 (v5.28.0) built for darwin-2level
[...]

[Amar1729]

Seems like it's a problem with shebang handling on Darwin.

$ nix-info -m
 - system: `"x86_64-darwin"`
 - host os: `Darwin 17.7.0, macOS 10.13.6`
 - multi-user?: `no`
 - sandbox: `no`
 - version: `nix-env (Nix) 2.1.3`
 - channels(paula1): `"nixpkgs-19.03pre155263.20c4986c4dd"`
 - nixpkgs: `/Users/paula1/.nix-defexpr/channels/nixpkgs`

This is the nix shebang for ack (spaces replaced with newlines for readability):

#!/nix/store/c5a3d01x5n14f97hr2ni45z39cbqm6hk-perl-5.28.0/bin/perl
-I/nix/store/c5a3d01x5n14f97hr2ni45z39cbqm6hk-perl-5.28.0/lib/perl5/site_perl
-I/nix/store/3fkxk27px7ajvf6akrfna3kmsnf34hv7-perl5.28.0-File-Next-1.16/lib/perl5/site_perl
-I/nix/store/c5a3d01x5n14f97hr2ni45z39cbqm6hk-perl-5.28.0/lib/perl5/site_perl
-I/nix/store/3fkxk27px7ajvf6akrfna3kmsnf34hv7-perl5.28.0-File-Next-1.16/lib/perl5/site_perl
-I/nix/store/c5a3d01x5n14f97hr2ni45z39cbqm6hk-perl-5.28.0/lib/perl5/site_perl
-I/nix/store/3fkxk27px7ajvf6akrfna3kmsnf34hv7-perl5.28.0-File-Next-1.16/lib/perl5/site_perl
-I/nix/store/93i93v14dsmvvb1p06ny9sdwirhz4gca-perl5.28.0-ack-2.24/lib/perl5/site_perl

Manually calling /nix/store/c5a3d01x5n14f97hr2ni45z39cbqm6hk-perl-5.28.0/bin/perl works fine. Deleting the shebang from the ack script and calling it manually like this works:
/nix/store/c5a3d01x5n14f97hr2ni45z39cbqm6hk-perl-5.28.0/bin/perl -I/nix/store/3fkxk27px7ajvf6akrfna3kmsnf34hv7-perl5.28.0-File-Next-1.16/lib/perl5/site_perl bin/ack --help

So I just removed the duplicate paths from the ack shebang and it works fine:

#!/nix/store/c5a3d01x5n14f97hr2ni45z39cbqm6hk-perl-5.28.0/bin/perl
-I/nix/store/3fkxk27px7ajvf6akrfna3kmsnf34hv7-perl5.28.0-File-Next-1.16/lib/perl5/site_perl
-I/nix/store/93i93v14dsmvvb1p06ny9sdwirhz4gca-perl5.28.0-ack-2.24/lib/perl5/site_perl
-I/nix/store/c5a3d01x5n14f97hr2ni45z39cbqm6hk-perl-5.28.0/lib/perl5/site_perl

Not sure why this problem exists though. Maybe duplicate include directories in shebangs should be fixed in the buildPerlPackage function?

[Amar1729]

Interestingly, on mac just calling it from cli explicitly works:
/nix/store/c5a3d01x5n14f97hr2ni45z39cbqm6hk-perl-5.28.0/bin/perl -I/nix/store/c5a3d01x5n14f97hr2ni45z39cbqm6hk-perl-5.28.0/lib/perl5/site_perl -I/nix/store/3fkxk27px7ajvf6akrfna3kmsnf34hv7-perl5.28.0-File-Next-1.16/lib/perl5/site_perl -I/nix/store/c5a3d01x5n14f97hr2ni45z39cbqm6hk-perl-5.28.0/lib/perl5/site_perl -I/nix/store/3fkxk27px7ajvf6akrfna3kmsnf34hv7-perl5.28.0-File-Next-1.16/lib/perl5/site_perl -I/nix/store/c5a3d01x5n14f97hr2ni45z39cbqm6hk-perl-5.28.0/lib/perl5/site_perl -I/nix/store/3fkxk27px7ajvf6akrfna3kmsnf34hv7-perl5.28.0-File-Next-1.16/lib/perl5/site_perl -I/nix/store/93i93v14dsmvvb1p06ny9sdwirhz4gca-perl5.28.0-ack-2.24/lib/perl5/site_perl /nix/store/93i93v14dsmvvb1p06ny9sdwirhz4gca-perl5.28.0-ack-2.24/bin/ack --help

[Calvin-L]

That shebang line is awful long. Could it be that MacOS has some maximum length for the shebang line? That would explain why shortening the line makes it work. If Bash has a longer maximum command length, then it also explains why invoking perl directly from Bash works.

[Calvin-L]

This issue might be a duplicate of #35353, which is looking into buildPerlModule creating shebang lines that are too long for Darwin systems.

[Amar1729]

This stackoverflow solution is an interesting workaround - could maybe considered as wrapper logic for buildPerlModule on darwin

#!/bin/bash
script="$1" 
shebang=$(head -1 "$script")
interp=( ${shebang#\#!} )        # use an array in case a argument is there too
# now run it
exec "${interp[@]}" "$script"

[cyounkins]

I can confirm modifying the shebang to remove the duplicate includes fixes ack. I agree it appears to be the line length. Good find, this was puzzling!

[dropwhile]

@Calvin-L On macos, I was able to install ack with nix-env -i -A nixpkgs.ack.
nix-env -i ack also did not work for me.

Got the same error though due to shebang line length