$ ls -l setup.bz2*; md5sum setup.bz2* -rw-r--r--+ 1 kou None 2066818 Feb 23 08:40 setup.bz2 -rw-r--r--+ 1 kou None 72 Feb 23 12:10 setup.bz2.sig 1104e25d6b0cfc643febf39d689ca362 *setup.bz2 9a1eabe88e3f8d86b8724883d55381ab *setup.bz2.sig $ gpg --keyring pubring.gpg setup.bz2.sig gpg: assuming signed data in `setup.bz2' gpg: Signature made Tue Feb 23 12:10:32 2016 JST using DSA key ID 676041BA gpg: Good signature from "Cygwin <cygwin@cygwin.com>" gpg: WARNING: This key is not certified with a trusted signature! gpg: There is no indication that the signature belongs to the owner. Primary key fingerprint: 1169 DF9F 2273 4F74 3AA5 9232 A9A2 62FF 6760 41BA $ wget -N -c http://ftp.jaist.ac.jp/pub/cygwin/x86_64/setup.bz2 http://ftp.jaist.ac.jp/pub/cygwin/x86_64/setup.bz2.sig --2016-02-25 18:27:17-- http://ftp.jaist.ac.jp/pub/cygwin/x86_64/setup.bz2 Resolving ftp.jaist.ac.jp (ftp.jaist.ac.jp)... 150.65.7.130, 2001:df0:2ed:feed::feed Connecting to ftp.jaist.ac.jp (ftp.jaist.ac.jp)|150.65.7.130|:80... connected. HTTP request sent, awaiting response... 206 Partial Content Length: 2073038 (2.0M), 6220 (6.1K) remaining [application/x-bzip2] Saving to: ‘setup.bz2’ setup.bz2 100%[+++++++++++++++++++>] 1.98M --.-KB/s in 0s 2016-02-25 18:27:17 (237 MB/s) - ‘setup.bz2’ saved [2073038/2073038] --2016-02-25 18:27:17-- http://ftp.jaist.ac.jp/pub/cygwin/x86_64/setup.bz2.sig Reusing existing connection to ftp.jaist.ac.jp:80. HTTP request sent, awaiting response... 416 Requested Range Not Satisfiable The file is already fully retrieved; nothing to do. FINISHED --2016-02-25 18:27:17-- Total wall clock time: 0.1s Downloaded: 1 files, 6.1K in 0s (237 MB/s) $ ls -l setup.bz2*; md5sum setup.bz2* -rw-r--r--+ 1 kou None 2073038 Feb 25 15:10 setup.bz2 -rw-r--r--+ 1 kou None 72 Feb 23 12:10 setup.bz2.sig ff5c8d90234240671eac9cb47f09cb30 *setup.bz2 9a1eabe88e3f8d86b8724883d55381ab *setup.bz2.sig $ gpg --keyring pubring.gpg setup.bz2.sig gpg: assuming signed data in `setup.bz2' gpg: Signature made Tue Feb 23 12:10:32 2016 JST using DSA key ID 676041BA gpg: BAD signature from "Cygwin <cygwin@cygwin.com>"-N オプションのみにすれば以下のように更新されるが、この場合、-c がないため download が未完了だった場合 resume されない。
$ ls -l setup.bz2*; md5sum setup.bz2* -rw-r--r--+ 1 kou None 2066818 Feb 23 08:40 setup.bz2 -rw-r--r--+ 1 kou None 72 Feb 23 12:10 setup.bz2.sig 1104e25d6b0cfc643febf39d689ca362 *setup.bz2 9a1eabe88e3f8d86b8724883d55381ab *setup.bz2.sig $ wget -N http://ftp.jaist.ac.jp/pub/cygwin/x86_64/setup.bz2 http://ftp.jaist.ac.jp/pub/cygwin/x86_64/setup.bz2.sig --2016-02-25 18:30:11-- http://ftp.jaist.ac.jp/pub/cygwin/x86_64/setup.bz2 Resolving ftp.jaist.ac.jp (ftp.jaist.ac.jp)... 150.65.7.130, 2001:df0:2ed:feed::feed Connecting to ftp.jaist.ac.jp (ftp.jaist.ac.jp)|150.65.7.130|:80... connected. HTTP request sent, awaiting response... 200 OK Length: 2073038 (2.0M) [application/x-bzip2] Saving to: ‘setup.bz2’ setup.bz2 100%[===================>] 1.98M 4.87MB/s in 0.4s 2016-02-25 18:30:12 (4.87 MB/s) - ‘setup.bz2’ saved [2073038/2073038] --2016-02-25 18:30:12-- http://ftp.jaist.ac.jp/pub/cygwin/x86_64/setup.bz2.sig Reusing existing connection to ftp.jaist.ac.jp:80. HTTP request sent, awaiting response... 200 OK Length: 72 [application/pgp-signature] Saving to: ‘setup.bz2.sig’ setup.bz2.sig 100%[===================>] 72 --.-KB/s in 0s 2016-02-25 18:30:12 (3.13 MB/s) - ‘setup.bz2.sig’ saved [72/72] FINISHED --2016-02-25 18:30:12-- Total wall clock time: 0.6s Downloaded: 2 files, 2.0M in 0.4s (4.87 MB/s) $ ls -l setup.bz2*; md5sum setup.bz2* -rw-r--r--+ 1 kou None 2073038 Feb 25 15:10 setup.bz2 -rw-r--r--+ 1 kou None 72 Feb 25 18:10 setup.bz2.sig 2974e4ff8f13a019ed48cf25100a8d4b *setup.bz2 4704b624aa98d624f2da1762810059b7 *setup.bz2.sig $ gpg --keyring pubring.gpg setup.bz2.sig gpg: assuming signed data in `setup.bz2' gpg: Signature made Thu Feb 25 18:10:39 2016 JST using DSA key ID 676041BA gpg: Good signature from "Cygwin <cygwin@cygwin.com>" gpg: WARNING: This key is not certified with a trusted signature! gpg: There is no indication that the signature belongs to the owner. Primary key fingerprint: 1169 DF9F 2273 4F74 3AA5 9232 A9A2 62FF 6760 41BA-N -c を併用した場合の正しい動作は、