bash-if 块不起作用
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bash-if block not working
提问by Monojit
I have below code.The logic here is if HostList conatains any blanck entry it should set class as blank, else it should be red.Now I am getting error-
我有下面的代码。这里的逻辑是，如果 HostList 包含任何空白条目，它应该将类设置为空白，否则它应该是红色的。现在我收到错误 -
test.sh[3]: syntax error at line 7 : `then' unexpected
test.sh[3]：第 7 行的语法错误：“然后”意外
can any one help me out?Thanks!!
任何人都可以帮助我吗？谢谢！
#! /bin/bash
file=./HostList.txt
{
echo "<table>"
printf "<tr>"
if[%s -eq =""]; then
class="blank"
else
class="red"
fi
"<td" $class">%s</td>
<td>%s</td>
<td>%s</td>
<td>%s</td>
<td>%s</td>
<td>%s</td>
<td>%s</td>
<td>%s</td>
<td>%s</td>
<td>%s</td>
<td>%s</td>
<td>%s</td>
<td>%s</td>
</tr>\n" $(cat "$file"|cut -d'.' -f1)
echo "</table>"
} > table.html
exit 0
回答by user123444555621
Bash is very sensitive about whitespace. This should work:
Bash 对空格非常敏感。这应该有效：
if [ "%s" = "" ]; then
Note that =is used for string comparison and -eqis used for integers.
请注意，=用于字符串比较并-eq用于整数。
edit:
编辑：
More precisely, bash splits your original code like this:
更准确地说，bash 像这样拆分您的原始代码：
if[%s # supposedly a command
-eq # parameter
=""] # parameter
; # end of command
then # keyword
At this point, Bash realizes that there is an unmatchen thenkeyword, and doesn't even try to run if[%s(which would fail too).
此时，Bash 意识到存在一个不匹配的then关键字，并且甚至不会尝试运行if[%s（这也会失败）。
回答by paxdiablo
I'm not sure what all that HTML markup is doing in there but the ifstatement should be something like:
我不确定所有 HTML 标记在那里做什么，但if语句应该是这样的：
if [[ $something == "" ]] ; then
# do something
fi
In other words, you need some spaces between the brackets and the arguments, at a bare minimum.
换句话说，括号和参数之间至少需要一些空格。
回答by chepner
First, your ifstatement needs some spacing, and the -eqis unnecessary:
首先，您的if语句需要一些间距，并且-eq是不必要的：
if [ %s = "" ]; then
class="blank"
else
class="red"
fi
But more importantly, %sis not a variable, so you can't compare it to anything (or as pointed out in the comments, not usefully). It's just a placeholder for the printfcommand. You're going to have to be a little more explicit:
但更重要的是，%s它不是一个变量，所以你不能将它与任何东西进行比较（或者如评论中指出的那样，没有用）。它只是printf命令的占位符。你将不得不更明确一点：
hosts=($(cat "$file"))
echo "<table>"
echo "<tr>"
for host in ${hosts[@]}; do
host=$(echo $host | cut -d'.' -f1)
if [ "$host" = "" ]; then
echo "<td class='blank'>"
else
echo "<td class='red'>"
fi
done
echo "</tr>\n"
echo "</table>"
(The preceding has been minimally tested.)
（前面已经过最低限度的测试。）
