在 .sh 文件中使用 do 时出现“bash：数组和错误替换”
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/24808994/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
"bash: Array and Bad substitution" when using do in .sh file
提问by fdicarlo
I wuld like to create a script who run some program and check if they started or no, unfortunately I receive several error and I don't know why:
我想创建一个脚本来运行一些程序并检查它们是否启动，不幸的是我收到几个错误，我不知道为什么：
#!/bin/sh
# start file
c[0] = 'foo'
c[1] = 'mickey'
c[2] = 'mouse'
echo "Launching..."
for i in 0 1 2; do
echo "Starting ${c[i]}"
${c[i]}
ps cax | grep ${c[i]}
if [ $? -eq 0 ]; then
echo "${c[i]} is running"
else
{
echo "${c[i]} is not running"
${c[i]}
}
fi
done
echo "launch completed."
when I try to run it, the shell don't recognize both the command name and I receive error also on the line
当我尝试运行它时，shell 无法识别命令名称，并且我也在线上收到错误
for i in 0 1 2; do
for "Bad substitution".
为“坏替代”。
Can you please explain where I'm wrong with this script? Thanks in advance.
你能解释一下我对这个脚本的错误吗？提前致谢。
---- Update ----
- - 更新 - -
Thanks to us for your REALLY PRECIOUS answers, I modified my script according to your advices:
感谢我们为您提供非常宝贵的答案，我根据您的建议修改了我的脚本：
#!/bin/bash
# start file
echo "Launching..."
for i in foo mickey mouse; do
echo "Starting $i"
$i
ps cax | grep $i
if [ $? -eq 0 ]; then
echo "$i is running"
else
echo "$i is not running"
$i
fi
done
echo "launch completed."
Thanks again! Fabrizio
再次感谢！法布里齐奥
回答by scragar
OK, there's a few errors here, let's go through them from the start:
好的，这里有一些错误，让我们从头开始：
c[0] = 'foo'
c[1] = 'mickey'
c[2] = 'mouse'
cis undefined, and no spaces in assignments:
c未定义，并且赋值中没有空格：
c=()
c[0]='foo'
c[1]='mickey'
c[2]='mouse'
For
为了
echo "Starting ${c[i]}"
${c[i]}
ps cax | grep ${c[i]}
if [ $? -eq 0 ]; then
echo "${c[i]} is running"
else
{
echo "${c[i]} is not running"
${c[i]}
}
fi
You need to refer to ${c[$i]} to access the index, $c[i] is referencing an index based on the character i, not the variable.
您需要引用 ${c[$i]} 来访问索引， $c[i] 引用的是基于字符的索引i，而不是变量。
echo "Starting ${c[$i]}"
${c[$i]}
ps cax | grep ${c[$i]}
if [ $? -eq 0 ]; then
echo "${c[$i]} is running"
else
{
echo "${c[$i]} is not running"
${c[$i]}
}
fi
Finally:
最后：
else
{
echo "${c[$i]} is not running"
${c[$i]}
}
fi
Bash doesn't use braces for if/else, get rid of them
Bash 不为 if/else 使用大括号，摆脱它们
else
echo "${c[$i]} is not running"
${c[$i]}
fi
All done.
全部完成。
回答by sun_dare
Please have a look at this code. Its not good to use 0 1 2 to iterate through the array because you might not know the size of the array. Its better to use ${c[@]} which would have all the elements of the array. This would be more dynamic and better
请看一下这段代码。使用 0 1 2 遍历数组并不好，因为您可能不知道数组的大小。最好使用 ${c[@]} ，它包含数组的所有元素。这会更有活力，更好
#!/bin/sh
# start file
c=(foo mickey mouse)
echo "Launching..."
//below one to execute your foo or micckyor mouse command
$i
for i in ${c[@]}; do
echo "Starting $i"
ps cax | grep $i
if [ $? -eq 0 ]; then
echo "$i is running"
else
{
echo "$i is not running"
//below one to execute your foo or micckyor mouse command
$i
}
fi
done
echo "launch completed."
回答by jrjc
You need to change
你需要改变
c[0] = 'foo'
c[1] = 'mickey'
c[2] = 'mouse'
to
到
c[0]='foo'
c[1]='mickey'
c[2]='mouse'
