Question

我知道如何在bash中执行每次增加1的循环，但是我说我的范围是1到773，我想从循环中输出一个范围，这样我在每次迭代中得到两个变量。第一个将是1，第二个将是19.在第二个迭代中，第一个将是20，第二个是39.

我一直在玩类似的东西：

for start in {1..773}
do    
start=$(($start+20))
end=$(($start+20))
echo $start ## 
echo $end
done

期望的循环结果：

 1. $start = 1 and $end = 19
 2. $start = 20 and $end = 39
 3. $start = 40 and $end = 59 
etc

但这不对。我想将这两个变量输出到一系列脚本中以使R运行得更快，所以如果非bash（例如awk）解决方案更容易，那么如果简单的＆gt;那也很酷。会发送文件。

谢谢！

Answer 1

您的要求并不十分清楚，但您正在重复使用变量名称。

如果我这样做：

for index in {1..773}
do    
  start=$(($index+20))
  end=$(($start+20))
  echo $start ## 
  echo $end
done

我得到的东西类似于你想要的结果。观察我如何将循环变量从开始重命名为索引。

PS：如果你想在循环中改变步长（a.k.a。“increment”），只需这样做：

#!/bin/bash
for i in {0..10..2}
  do
     echo "Welcome $i times"
done

这将以2为步长增加，你想在这里使用20。这会给你1, 21, 41, ...作为价值。有关详细信息，请参阅http://www.cyberciti.biz/faq/bash-for-loop/。

Answer 2

如果要在773范围内打印范围，可以这样做

#!env bash
start=1
end=19
for counter in {1..773}
do
   echo $counter. "\$start = " $start " and \$end = " $end
   if [[ $start -eq 1 ]];
   then
      start=0
   fi
   start=$(($start+20))
   end=$(($end+20))
   if [[ $end -ge 773 ]];
   then
      break
   fi
done

<强>输出

1. $start =  1  and $end =  19
2. $start =  20  and $end =  39
3. $start =  40  and $end =  59
4. $start =  60  and $end =  79
5. $start =  80  and $end =  99
6. $start =  100  and $end =  119
7. $start =  120  and $end =  139
8. $start =  140  and $end =  159
9. $start =  160  and $end =  179
10. $start =  180  and $end =  199
11. $start =  200  and $end =  219
12. $start =  220  and $end =  239
13. $start =  240  and $end =  259
14. $start =  260  and $end =  279
15. $start =  280  and $end =  299
16. $start =  300  and $end =  319
17. $start =  320  and $end =  339
18. $start =  340  and $end =  359
19. $start =  360  and $end =  379
20. $start =  380  and $end =  399
21. $start =  400  and $end =  419
22. $start =  420  and $end =  439
23. $start =  440  and $end =  459
24. $start =  460  and $end =  479
25. $start =  480  and $end =  499
26. $start =  500  and $end =  519
27. $start =  520  and $end =  539
28. $start =  540  and $end =  559
29. $start =  560  and $end =  579
30. $start =  580  and $end =  599
31. $start =  600  and $end =  619
32. $start =  620  and $end =  639
33. $start =  640  and $end =  659
34. $start =  660  and $end =  679
35. $start =  680  and $end =  699
36. $start =  700  and $end =  719
37. $start =  720  and $end =  739
38. $start =  740  and $end =  759

Answer 3

您可以使用seq命令

for start in `seq 1 20 700`
do    
  echo $start $(($start+19))
done

seq的用法是：

$ seq --help
Usage: seq [OPTION]... LAST
  or:  seq [OPTION]... FIRST LAST
  or:  seq [OPTION]... FIRST INCREMENT LAST
Print numbers from FIRST to LAST, in steps of INCREMENT.

Answer 4

这是使用一致输出的一种方法：

for ((i = 1, start = 1, end = 19; i <= 773; ++i, start += 20, end += 20)); do
    echo "$i. \$start = $start and \$end = $end"
done

输出：

1. $start = 1 and $end = 19
2. $start = 21 and $end = 39
3. $start = 41 and $end = 59
4. $start = 61 and $end = 79

或者

for ((i = 1, start = 1, end = 19; i <= 773; ++i, start += 20, end += 20)); do
    echo "$i. \$start = $start and \$end = $end"
done

输出：

1. $start = 1 and $end = 20
2. $start = 21 and $end = 40
3. $start = 41 and $end = 60
4. $start = 61 and $end = 80

另：

for ((i = 1, start = 0, end = 19; i <= 773; ++i, start += 20, end += 20)); do
    echo "$i. \$start = $start and \$end = $end"
done

输出：

1. $start = 0 and $end = 19
2. $start = 20 and $end = 39
3. $start = 40 and $end = 59
4. $start = 60 and $end = 79

这样你可以有两个变量。

Answer 5

除非我遗漏了一些东西，否则你可以这样做：

for ((s=0,e=19; e<773; s+=20,e+=20)); do
    echo $s "-" $e
done

<强>输出：

Answer 6

没有人建议while循环

start=0 step=20 end=$((step - 1))
while (( end < 773 )); do
    echo "$start - $end"
    (( start += step, end += step ))
done

可生产

当然，while循环可以写成for循环：

for ((start=0, step=20, end=step-1; end < 773; start+=step, end+=step)); do ...

Answer 7

这是一种方法：

step=20
last=773

for ((i = 0; i <= $last; i += $step))
do
    start=$i

    end=$(($i + (($step - 1))))

    if (($end > $last))
    then
        end=$last
    fi

    echo "\$start: $start"
    echo "\$end: $end"
done

它基本上只是一个简单的for循环。

按设定量增加bash循环

7 个答案: