在我的 bash 脚本中找不到“let”命令
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"let" command is not found in my bash script
提问by user26767
I have the following bash script,
我有以下 bash 脚本，
#!/bin/bash
echo $SHELL
i=1
for img in ../img/*.png; do
echo $img
new=$(printf "../img/tmp/pyr%d.png" "$i")
echo $new
# cp "$img" "$new"
let i=i+1
done
# avconv -r 2 -i ../img/tmp/pyr%d.png -b:v 1000k ../pop_pyr.mp4
In the ../imgfolder, there are files pyr1920.png, pyr1925.png, ...
在../img文件夹中，有文件pyr1920.png, pyr1925.png, ...
When I run this script, I get this error
当我运行此脚本时，出现此错误
../img/pyr1920.png
../img/tmp/pyr1.png
make_video.sh: 10: make_video.sh: let: not found
../img/pyr1925.png
../img/tmp/pyr1.png
But I pasted the script in a terminal, it works perfectly fine.
但是我将脚本粘贴到终端中，它运行良好。
../img/pyr1920.png
../img/tmp/pyr1.png
../img/pyr1925.png
../img/tmp/pyr2.png
My environment it ubuntu 14.04. I understand that default /bin/sh is dash. I make sure to use bash and check by echo $SHELL.
我的环境是 ubuntu 14.04。我知道默认的 /bin/sh 是破折号。我确保使用 bash 并通过echo $SHELL.
Why it doesn't work as a script but works fine from a terminal? I tried to find a solution but all I can find is about "dash" and "bash" setting.
为什么它不能作为脚本工作但在终端上工作正常？我试图找到一个解决方案，但我能找到的只是关于“dash”和“bash”设置。
回答by Kent
do in this way:
这样做：
i=$((i+1))
or
或者
i=$(expr $i + 1)
回答by user26767
I am sorry for answering my question.
I was running my script with sh script.shnot bash script.sh. bash script.shworked fine.
我很抱歉回答我的问题。我正在用sh script.shnot运行我的脚本bash script.sh。bash script.sh工作正常。
But isn't that I can specify it by #!/bin/bashon the top of a script?
但是我不是可以#!/bin/bash在脚本顶部指定它吗？
回答by jhonxito
I also had the same error, checking I found that with this code you get what you need
我也有同样的错误，检查我发现用这个代码你得到了你需要的
i=`expr $i + 1`
