Fisher: Add requirements in README.md

[nagromc]

Fisherman seems to require bc:

$ fisher ls
env: bc: Aucun fichier ou dossier de ce type
rvm             ssh-agent
$ # Basically, it says that `bc` was not found. On Debian Jessie, I use the following command to install it
$ sudo apt-get install bc
# … successful instalation logs …
$ fisher ls
rvm             ssh-agent
$ # ↑ yay, no error 👍 ↑

It may be a good idea to add the requirement installation to README.md for every system (apt-get for Debian, brew for macOS, etc.)

Related issue: https://github.com/fisherman/fisherman/issues/113#issuecomment-187968096

[jorgebucaran]

@nagromc

Another idea, let's get rid of bc in favor of awk. Awk is definitely required, so it makes sense.

EDIT: Sorry about the weird duplicates.

[nagromc]

Well, do you mean I just need awk to be installed on the system, or it's just a memo for you?

At the moment, I do have awk pre-installed on my system:

$ fisher --version 
fisherman version 2.10.0 ~/.config/fish/functions/fisher.fish
$ sudo apt-get remove bc
# … successful uninstalation logs …
$ which awk
/usr/bin/awk
$ fisher ls
env: bc: Aucun fichier ou dossier de ce type
rvm             ssh-agent
$ # oh noes ☹

Actually, I've no idea why bc is needed.

[jorgebucaran]

@nagromc Sorry for the confusion. What I am saying is I'll cut a new release removing any incidence of bc with a functional equivalent using awk. This way fisherman is only dependent in awk.

[nagromc]

Great! So I let you close this issue whenever you find it appropriate. To me, it is a now a known bug and I know you'll fix it soon.

Thanks.

[jorgebucaran]

Hi @nagromc. I'm sorry it has taken me forever to answer this issue properly. bc is not really used anywhere in fisherman. But I know that fish's native math function uses bc under the hood. Do you still have this problem?

Perhaps you can check if fish's native math function works for you?

math "3.14*2"

[nagromc]

That's okay @jbucaran Don't worry about that 😉

You seem to be right. bc is needed by fish:

$ bc --version
bc 1.06.95
Copyright 1991-1994, 1997, 1998, 2000, 2004, 2006 Free Software Foundation, Inc.
$ sudo apt-get remove bc
Lecture des listes de paquets... Fait
Construction de l'arbre des dépendances
Lecture des informations d'état... Fait
Les paquets suivants ont été installés automatiquement et ne sont plus nécessaires :
  rlwrap xsel
Veuillez utiliser « apt-get autoremove » pour les supprimer.
Les paquets suivants seront ENLEVÉS :
  bc fish fish-common
0 mis à jour, 0 nouvellement installés, 3 à enlever et 0 non mis à jour.
Après cette opération, 8 565 ko d'espace disque seront libérés.
Souhaitez-vous continuer ? [O/n] n
Annulation.
$ # basically, it says that `bc` `fish` and `fish-common` will be removed
$ math "3.14*2"
6.28
$ lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description:    Debian GNU/Linux 8.7 (jessie)
Release:        8.7
Codename:       jessie

Those are the logs from a "real" Debian Jessie 8.7. I think my mistake comes from using Raspbian where I installed fish manually -- the version I needed not being available on the repo at the moment I stumbled upon the issue.

Thanks for your time.