blocks|key|1235764|text|试试for的算术表达式版本|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1235765|max=10
for+((+i=2;+i+<=+$max;+%2B%2Bi+))
do
++++echo+"$i"
done|code-block|syntax|javascript|1235766|这在bash的大多数版本中都可用，并且还应该与Bourne+shell+(sh)兼容。|1235767|entityMap^0|2|3|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

Try the arithmetic-expression version of <code>for</code>:

<pre><code>max=10
for (( i=2; i &lt;= $max; ++i ))
do
 echo "$i"
done
</code></pre>

This is available in most versions of bash, and should be Bourne shell (sh) compatible also.

blocks|key|1450472|text|如果seq命令在您的系统上可用：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1450473|for+i+in+`seq+2+$max`
do
++echo+"output:+$i"
done|code-block|syntax|javascript|1450474|如果不是，那么在perl中使用可怜人的seq|1450475|seq=`perl+-e+"\$,='+';print+2..$max"`
for+i+in+$seq
do
++echo+"output:+$i"
done|1450476|注意那些引号。|1450477|entityMap^0|2|3|0|0|8|4|J|3|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|M|3|N|5|H|7|11|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|12|8|@]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|13|8|@]|D|@]|E|$]]]|R|$]]

If the <code>seq</code> command available on your system:

<pre><code>for i in `seq 2 $max`
do
 echo "output: $i"
done
</code></pre>

If not, then use poor man's <code>seq</code> with <code>perl</code>:

<pre><code>seq=`perl -e "\$,=' ';print 2..$max"`
for i in $seq
do
 echo "output: $i"
done
</code></pre>

Watch those quote marks.

blocks|key|1450537|text|有不止一种方法可以做到这一点。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1450538|max=10
for+i+in+`eval+"echo+{2..$max}"`
do
++++echo+"$i"
done|code-block|syntax|javascript|1450539|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

There's more than one way to do it.

<pre><code>max=10
for i in `eval "echo {2..$max}"`
do
 echo "$i"
done
</code></pre>

blocks|key|1236029|text|我们可以像C编程一样迭代循环。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1236030|#!/bin/bash
for+((i=1;+i<=20;+i=i%2B1))
do+
++++++echo+$i
done|code-block|syntax|javascript|1236031|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

We can iterate loop like as C programming.

<pre><code>#!/bin/bash
for ((i=1; i&lt;=20; i=i+1))
do 
 echo $i
done
</code></pre>

blocks|key|1235949|text|这是一种方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1235950|Bash：|1235951|max=10
for+i+in+$(bash+-c+"echo+{2..${max}}");+do+echo+$i;+done|code-block|syntax|javascript|1235952|当分别将bash+-c替换为ksh+-c或zsh+-c时，上述Bash方法也适用于ksh和zsh。|offset|length|style|CODE|1235953|注意：for+i+in+{2..${max}};+do+echo+$i;+done可以在zsh和ksh中工作。|1235954|entityMap^0|0|0|0|4|7|E|6|L|6|15|3|19|3|0|3|12|18|3|1C|3|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|V|8|@$K|W|L|X|M|N]|$K|Y|L|Z|M|N]|$K|10|L|11|M|N]|$K|12|L|13|M|N]|$K|14|L|15|M|N]]|9|@]|A|$]]|$1|O|3|P|5|6|7|16|8|@$K|17|L|18|M|N]|$K|19|L|1A|M|N]|$K|1B|L|1C|M|N]]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|1D|8|@]|9|@]|A|$]]]|R|$]]

This is a way: 
Bash:

<pre><code>max=10
for i in $(bash -c "echo {2..${max}}"); do echo $i; done
</code></pre>

The above Bash way will work for <code>ksh</code> and <code>zsh</code> too, when <code>bash -c</code> is replaced with <code>ksh -c</code> or <code>zsh -c</code> respectively.

Note: <code>for i in {2..${max}}; do echo $i; done</code> works in <code>zsh</code> and <code>ksh</code>.

blocks|key|1235862|text|在这里，它在Mac+OS和X上工作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1235863|其中包括BSD日期的示例，以及如何同时递增和递减日期：|1235864|for+((i=28;+i>=6+;+i--));
do
++++dat=`date+-v-${i}d+-j+"%2B%25Y%25m%25d"`+
++++echo+$dat
done|code-block|syntax|javascript|1235865|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Here it worked on Mac&nbsp;OS&nbsp;X.

It includes the example of a BSD date, how to increment and decrement the date also:

<pre><code>for ((i=28; i&gt;=6 ; i--));
do
 dat=`date -v-${i}d -j "+%Y%m%d"` 
 echo $dat
done
</code></pre>

blocks|key|1235816|text|使用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1235817|max=10
for+i+in+`eval+echo+{2..$max}`
do
++++echo+$i
done|code-block|syntax|javascript|1235818|在变量替换后，您需要显式的“eval”调用来重新计算{}。|1235819|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Use:

<pre><code>max=10
for i in `eval echo {2..$max}`
do
 echo $i
done
</code></pre>

You need the explicit 'eval' call to reevaluate the {} after variable substitution.

blocks|key|1450749|text|这些都是{1..8}，应该都是POSIX。如果您将条件continue放入循环中，它们也不会中断。规范的方式：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1450750|f=
while+[+$((f%2B=1))+-le+8+]
do
++echo+$f
done|code-block|syntax|javascript|1450751|另一种方式：|1450752|g=
while
++g=${g}1
++[+${#g}+-le+8+]
do
++echo+${#g}
done|1450753|另一个是：|1450754|set+--
while
++set+$*+.
++[+${#}+-le+8+]
do
++echo+${#}
done|1450755|entityMap^0|4|6|R|8|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|Z|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|10|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|11|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|12|8|@]|D|@]|E|$]]|$1|Q|3|R|5|H|7|13|8|@]|D|@]|E|$I|J]]|$1|S|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|T|$]]

These all do <code>{1..8}</code> and should all be POSIX. They also will not break if you
put a conditional <code>continue</code> in the loop. The canonical way:

<pre><code>f=
while [ $((f+=1)) -le 8 ]
do
 echo $f
done
</code></pre>

Another way:

<pre><code>g=
while
 g=${g}1
 [ ${#g} -le 8 ]
do
 echo ${#g}
done
</code></pre>

and another:

<pre><code>set --
while
 set $* .
 [ ${#} -le 8 ]
do
 echo ${#}
done
</code></pre>

I have gotten the following to work:

<pre><code>for i in {2..10}
do
 echo "output: $i"
done
</code></pre>

It produces a bunch of lines of <code>output: 2</code>, <code>output: 3</code>, so on.

However, trying to run the following:

<pre><code>max=10
for i in {2..$max}
do
 echo "$i"
done
</code></pre>

produces the following:

<pre><code>output: {2..10}
</code></pre>

How can I get the compiler to realize it should treat $max as the other end of the array, and not part of a string?

Shell script "for" loop syntax

编译器

我已经让以下内容生效了：for i in {2..10}do    echo "output: $i"done它会生成一系列的output: 2、output: 3等代码行。但是，尝试运行以下命令：max=10for i in {2..$max}do    echo "$i"done生成以下内容：output: {2..10}如何让编译器意识到它应该将$max视为数组的另一端，而不是字符串的一部分

问Shell脚本"for“循环语法
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