如何使用bash中可用的工具生成范围内所有日期的列表? [英] How to generate a list of all dates in a range using the tools available in bash?
问题描述
我想下载一堆以ISO-8601日期命名的文件.有没有简单的方法可以使用bash + GNU coreutils来做到这一点?(或一些使wget/curl自动生成列表的技巧,但我发现不太可能)
I want to download a bunch of files named with ISO-8601 dates. Is there a simple way to do this using bash+GNU coreutils? (Or some trick to make wget/curl to generate the list automatically, but I find that unlikely)
Similar to this question, but not restricted to weekdays: How to generate a range of nonweekend dates using tools available in bash?. I guess that there is a simpler way to do it without that restriction.
还与>如何生成日期范围有关bash上的随机数据,但不限于一年.
推荐答案
If you have GNU date
, you could do use either a for
loop in any POSIX-compliant shell:
# with "for"
for i in {1..5}; do
# ISO 8601 (e.g. 2020-02-20) using -I
date -I -d "2014-06-28 +$i days"
# custom format using +
date +%Y/%m/%d -d "2014-06-28 +$i days"
done
或 until
循环,这一次使用Bash的扩展测试 [[
:
or an until
loop, this time using Bash's extended test [[
:
# with "until"
d="2014-06-29"
until [[ $d > 2014-07-03 ]]; do
echo "$d"
d=$(date -I -d "$d + 1 day")
done
请注意,如果您将条件更改为 ["$ d" \> ;,则
. sh
的非古代版本也将进行词典编目比较.2014-07-03]
Note that non-ancient versions of sh
will also do lexicographical comparison if you change the condition to [ "$d" \> 2014-07-03 ]
.
这两个循环之一的输出:
Output from either of those loops:
2014-06-29
2014-06-30
2014-07-01
2014-07-02
2014-07-03
对于执行相同操作的更便携式方法,可以使用Perl脚本:
For a more portable way to do the same thing, you could use a Perl script:
use strict;
use warnings;
use Time::Piece;
use Time::Seconds;
use File::Fetch;
my ($t, $end) = map { Time::Piece->strptime($_, "%Y-%m-%d") } @ARGV;
while ($t <= $end) {
my $url = "http://www.example.com/" . $t->strftime("%F") . ".log";
my $ff = File::Fetch->new( uri => $url );
my $where = $ff->fetch( to => '.' ); # download to current directory
$t += ONE_DAY;
}
Time :: Piece,Time :: Seconds和File :: Fetch都是核心模块.像 perl wget.pl 2014-06-29 2014-07-03
一样使用它.
Time::Piece, Time::Seconds and File::Fetch are all core modules. Use it like perl wget.pl 2014-06-29 2014-07-03
.
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