Instalação do Docker no Linux: curl ou wget ?

Me perguntaram qual a diferença entre usar o curl ou wget para instalar o Docker no Linux. Aqui vai a resposta:

wget -qO- https://get.docker.com/ | sh

OU

curl -sSL https://get.docker.com/ | sh

Essencialmente ambos os comandos fazem a mesma coisa neste caso. A opção do curl é para ser usada em ambientes que não possuem wget por padrão como o MAC OSX, por exemplo.

Ambos jogam a saída para a standard output no modo silencioso. No curl é necessário indicar que ele deve seguir o redirecionamento, caso exista.

Indo pra saída padrão é possível redirecionar para a Shell /bin/sh e executar imediatamente a instalação.

Veja o help dos comandos abaixo. 

wget

-q, --quiet : Turn off Wget's output.
-O file, --output-document=file : The documents will not be written to the appropriate files, but all will be concatenated together and written to file. If - is used as file, documents will be printed to standard output

curl

-s, --silent : Silent  or  quiet  mode.  Don't  show  progress meter or error messages. 
-S, --show-error : When used with -s it makes curl show an error message if it fails.
-L, --location : If the server reports that the requested page has moved to a different location (indicated with a Location: header  and  a  3XX  response  code),  this option  will  make  curl  redo the request on the new place.

Eu pessoalmente prefiro o curl, que é muito mais poderoso.

Se você precisar de recursividade no processo de download, use o wget pois o curl não faz isso.


Deixe seu nome e e-mail para que eu possa enviar cupons de desconto para o curso sobre Docker


Para quem desejar mais detalhes sobre as diferenças entre os comandos veja esta explicação em inglês. Se precisarem de ajuda entre em contato.

What both commands do

  • both are command line tools that can download contents from FTP, HTTP and HTTPS
  • both can send HTTP POST requests
  • both support HTTP cookies
  • both are designed to work without user interaction, like from within scripts
  • both are fully open source and free software
  • both projects were started in the 90s
  • both support metalink

How they differ

curl

  • library. curl is powered by libcurl – a cross-platform library with a stable API that can be used by each and everyone. This difference is major since it creates a completely different attitude on how to do things internally. It is also slightly harder to make a library than a “mere” command line tool.
  • pipes. curl works more like the traditional unix cat command, it sends more stuff to stdout, and reads more from stdin in a “everything is a pipe” manner. Wget is more like cp, using the same analogue.
  • Single shot. curl is basically made to do single-shot transfers of data. It transfers just the URLs that the user specifies, and does not contain any recursive downloading logic nor any sort of HTML parser.
  • More protocols supported. curl supports FTP, FTPS, Gopher, HTTP, HTTPS, SCP, SFTP, TFTP, TELNET, DICT, LDAP, LDAPS, FILE, POP3, IMAP, SMB/CIFS, SMTP, RTMP and RTSP. Wget only supports HTTP, HTTPS and FTP.
  • More portable. curl builds and runs on lots of more platforms than wget. For example: OS/400, TPF and other more “exotic” platforms that aren’t straight-forward unix clones.
  • More SSL libraries and SSL support. curl can be built with one out of eleven (11!) different SSL/TLS libraries, and it offers more control and wider support for protocol details. curl supports public key pinning.
  • HTTP auth. curl supports more HTTP authentication methods, especially over HTTP proxies: Basic, Digest, NTLM and Negotiate
  • SOCKS support. curl supports several SOCKS protocol versions for proxy access
  • Bidirectional. curl offers upload and sending capabilities. Wget only offers plain HTTP POST support.
  • HTTP multipart/form-data sending, which allows users to do HTTP “upload” and in general emulate browsers and do HTTP automation to a wider extent
  • curl supports gzip and inflate Content-Encoding and does automatic decompression
  • curl offers and performs decompression of Transfer-Encoded HTTP, wget doesn’t
  • curl supports HTTP/2 and it does dual-stack connects using Happy Eyeballs
  • Much more developer activity. While this can be debated, I consider three metrics here: mailing list activity, source code commit frequency and release frequency. Anyone following these two projects can see that the curl project has a lot higher pace in all these areas, and it has been so for 10+ years. Compare on openhub

Wget

  • Wget is command line only. There’s no library.
  • Recursive! Wget’s major strong side compared to curl is its ability to download recursively, or even just download everything that is referred to from a remote resource, be it a HTML page or a FTP directory listing.
  • Older. Wget has traces back to 1995, while curl can be tracked back no earlier than the end of 1996.
  • GPL. Wget is 100% GPL v3. curl is MIT licensed.
  • GNU. Wget is part of the GNU project and all copyrights are assigned to FSF. The curl project is entirely stand-alone and independent with no organization parenting at all with almost all copyrights owned by Daniel.
  • Wget requires no extra options to simply download a remote URL to a local file, while curl requires -o or -O.
  • Wget supports the Public Suffix List for handling cookie domains, curl does not.
  • Wget supports only GnuTLS or OpenSSL for SSL/TLS support
  • Wget supports only Basic auth as the only auth type over HTTP proxy
  • Wget has no SOCKS support
  • Its ability to recover from a prematurely broken transfer and continue downloading has no counterpart in curl.
  • Wget can be typed in using only the left hand on a qwerty keyboard!