bash 如何在执行前打印每个命令？
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How can I print each command before executing?
提问by Frank
What is the best way to set up a Bash script that prints each command before it executes it?
设置在执行每个命令之前打印每个命令的 Bash 脚本的最佳方法是什么？
That would be great for debugging purposes.
这对于调试目的来说非常有用。
I already tried this:
我已经试过了：
CMD="./my-command --params >stdout.txt 2>stderr.txt"
echo $CMD
`$CMD`
It's supposed to print this first:
它应该先打印：
./my-command --params >stdout.txt 2>stderr.txt
And then execute ./my-command --params, with the output redirected to the files specified.
然后执行./my-command --params，将输出重定向到指定的文件。
回答by sehe
set -o xtrace
or
或者
bash -x myscript.sh
This works with standard /bin/sh as well IIRC (it might be a POSIX thing then)
这适用于标准 /bin/sh 以及 IIRC（它可能是 POSIX 的事情）
And remember, there is bashdb(bash Shell Debugger, release 4.0-0.4)
请记住，有bashdb( bash Shell Debugger, release 4.0-0.4)
To revert to normal, exit the subshell or
要恢复正常，请退出子外壳或
set +o xtrace
回答by geekosaur
The easiest way to do this is to let bashdo it:
最简单的方法是让bash这样做：
set -x
Or run it explicitly as bash -x myscript.
或者将其显式运行为bash -x myscript.
回答by VDarricau
set -xis fine, but if you do something like:
set -x很好，但是如果您执行以下操作：
set -x;
command;
set +x;
it would result in printing
它会导致打印
+ command
+ set +x;
You can use a subshell to prevent that such as:
您可以使用子shell来防止这种情况，例如：
(set -x; command)
which would just print the command.
这只会打印命令。
