Objective-C shell 转义

发布于 2024-10-13 06:49:39 字数 217 浏览 2 评论 0原文

如何在 ObjectivesC 中转义 shell 命令的参数？

ruby 库有 Shellwords （shellescape 用于 NSString，shelljoin 用于 NSArray，我不需要 shellsplit）。我确实需要一个转义字符串，我知道 NSTask，我不需要执行该命令。

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任性一次 2024-10-20 06:49:39

如果使用单引号，则转义 shell 的内容非常容易。了解 shell 引用的重要一点是，您可以在同一参数中连接具有不同引用样式的字符串，甚至是不带引号的字符串。例如，'one one'two'third"four" 混合了所有 3 种引用样式，并最终将字符串“onetwothirdfour”作为单个参数传递。另一件需要理解的事情是，除了引用之外，您还可以反斜杠转义特殊字符。最终结果是像 'one 二'\''三四' 这样的字符串，其计算结果为带有单引号的字符串“一二'三四”。通过使用此技巧，您可以轻松地引用任何字符串，方法是将所有单引号替换为序列 '\''，然后将整个字符串括在一对单引号中。

如果您有以下字符串：

I don't like shell quoting

并且应用了这个简单的转换，您最终会得到结果

'I don'\''t like shell quoting'

，并且 shell 会将其计算回原始字符串并作为单个参数进行处理。

NSString 上的以下类别应该可以轻松完成此转换：

@implementation NSString (ShellQuoting)
// prefixed with "my", replace with your prefix of choice
- (NSString *)myStringByShellquotingString:(NSString *)str {
    NSMutableString *result = [NSMutableString stringWithString:str];
    [result replaceOccurrencesOfString:@"'" withString:@"'\\''" options:0 range:NSMakeRange(0, [result length])];
    [result insertString:@"'" atIndex:0];
    [result appendString:@"'"];
    return result;
}
@end

Escaping content for the shell is pretty easy if you use single quotes. The important thing to understand about shell quoting is that you can concatenate strings with different quoting styles, and even unquoted strings, in the same argument. For example, 'one two'three" four" mixes all 3 quoting styles, and ends up passing the string "one twothree four" as a single argument. The other thing to understand is that outside of quoting, you can backslash-escape special characters. The end result of this is a string like 'one two'\''three four' evaluates to the string "one two'three four", with the single quote. By using this trick, you can easily quote any string by replacing all single-quotes with the sequence '\'' and then wrapping the entire string in a single pair of single quotes.

If you have the following string:

I don't like shell quoting

and you apply this simple transformation you end up with

'I don'\''t like shell quoting'

and this gets evaluated back to the original string by the shell and handled as a single argument.

The following category on NSString should accomplish this transformation easily:

@implementation NSString (ShellQuoting)
// prefixed with "my", replace with your prefix of choice
- (NSString *)myStringByShellquotingString:(NSString *)str {
    NSMutableString *result = [NSMutableString stringWithString:str];
    [result replaceOccurrencesOfString:@"'" withString:@"'\\''" options:0 range:NSMakeRange(0, [result length])];
    [result insertString:@"'" atIndex:0];
    [result appendString:@"'"];
    return result;
}
@end

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