我找到了这个关于如何下载文件的网站,其中的时间戳确实发生了变化:
https://www.gnu.org/software/wget/manual/html_node/Time_002dStamping-Usage.html
我试过了,但 wget 总是不断重新下载。但时间戳没有改变。我在这里不明白什么?
[tom@machine Downloads]$ ll
total 48536
-rw-r--r-- 1 tom students 49693179 Apr 5 07:22 assembly_summary_genbank.txt
[tom@machine Downloads]$ wget -N ftp://ftp.ncbi.nlm.nih.gov/genomes/genbank/assembly_summary_genbank.txt
--2018-04-05 18:24:42-- ftp://ftp.ncbi.nlm.nih.gov/genomes/genbank/assembly_summary_genbank.txt
=> ‘.listing’
Resolving ftp.ncbi.nlm.nih.gov (ftp.ncbi.nlm.nih.gov)... 165.112.9.229, 2607:f220:41e:250::11
Connecting to ftp.ncbi.nlm.nih.gov (ftp.ncbi.nlm.nih.gov)|165.112.9.229|:21... connected.
Logging in as anonymous ... Logged in!
==> SYST ... done. ==> PWD ... done.
==> TYPE I ... done. ==> CWD (1) /genomes/genbank ... done.
==> PASV ... done. ==> LIST ... done.
.listing [ <=> ] 1.11K --.-KB/s in 0.002s
2018-04-05 18:24:44 (449 KB/s) - ‘.listing’ saved [1133]
Removed ‘.listing’.
--2018-04-05 18:24:44-- ftp://ftp.ncbi.nlm.nih.gov/genomes/genbank/assembly_summary_genbank.txt
=> ‘assembly_summary_genbank.txt’
==> CWD not required.
==> SIZE assembly_summary_genbank.txt ... 49693179
==> PASV ... done. ==> RETR assembly_summary_genbank.txt ... done.
Length: 49693179 (47M) (unauthoritative)
assembly_summary_genbank.txt 100%[=====================================================================================================================>] 47.39M 5.44MB/s in 9.1s
2018-04-05 18:24:54 (5.20 MB/s) - ‘assembly_summary_genbank.txt’ saved [49693179]
[tom@machine Downloads]$ ll
total 48536
-rw-r--r-- 1 tom students 49693179 Apr 5 07:22 assembly_summary_genbank.txt