Is there any way to throw errors or warnings in a KornShell (ksh) script to prevent the use of unset variables? Let's assume I have a temporary folder that I want to remove.
有没有办法在KornShell(ksh)脚本中抛出错误或警告,以防止使用未设置的变量?假设我有一个我想删除的临时文件夹。
TEMP_FILES_DIR='/app/myapp/tmp'
rm -Rf $TEMP_FILE_DIR #notice the misspelling
How to prevent this kind of mistakes before they actually happen?
如何在实际发生之前预防这种错误?
I know the script should check for file existence and empty string before attempting to remove, this is just a silly example to illustrate a mistake that could have been avoided with some warnings. I don't know if this feature exists in ksh. If it does exist, how do you turn it on?
我知道脚本应该在尝试删除之前检查文件是否存在和空字符串,这只是一个愚蠢的例子来说明一些警告可以避免的错误。我不知道ksh中是否存在此功能。如果它确实存在,你如何打开它?
2 个解决方案
#1
6
The command
set -u
Will cause POSIX sh(1) and its derivatives to grouse when an attempt to expand an unset variable is made.
当尝试扩展未设置的变量时,将导致POSIX sh(1)及其衍生物发挥作用。
Example:
$ echo $foo $ set -u $ echo $foo sh: foo: parameter not set
#2
0
You could check the variable for having content, ie not being '', and print-out a message like "the variable is empty".
您可以检查变量是否有内容,即不是'',并打印出“变量为空”之类的消息。
However, that's still not going to fix PEBCAK errors like this - all you'd know is that nothing happened.
然而,这仍然不会像这样修复PEBCAK错误 - 所有你知道的是没有发生任何事情。
#1
6
The command
set -u
Will cause POSIX sh(1) and its derivatives to grouse when an attempt to expand an unset variable is made.
当尝试扩展未设置的变量时,将导致POSIX sh(1)及其衍生物发挥作用。
Example:
$ echo $foo $ set -u $ echo $foo sh: foo: parameter not set
#2
0
You could check the variable for having content, ie not being '', and print-out a message like "the variable is empty".
您可以检查变量是否有内容,即不是'',并打印出“变量为空”之类的消息。
However, that's still not going to fix PEBCAK errors like this - all you'd know is that nothing happened.
然而,这仍然不会像这样修复PEBCAK错误 - 所有你知道的是没有发生任何事情。