xargs错误：文件名太长

Question

I have a file that has a list of malicious file names. There are many file names contains blank spaces. I need to find them and change their permissions. I have tried the following:

 grep -E  ". " suspicious.txt | xargs -0  chmod 000 

But I am getting an error:

:File name too long 

An ideas?

Answer 1

OK, you have one filename per line in your file, and the problem is that xargs without -0 will treat spaces and tabs as well as the newlines as file separators, while xargs with -0 expects the filenames to be separated by NUL characters and won't care about the newlines at all.

So turn the newlines into NUL s before feeding the result into the xargs -0 command:

grep -E  ". " suspicious.txt | tr '\n' '\0' | xargs -0 chmod 000

Answer 2

Update:

See Mark Reeds correct answer. This was wrong because nulls were needed for the filenames from the file, not the filenames generated by grep .

Original:

You need something more like this:

grep -Z -E  ". " suspicious.txt | xargs -0  chmod 000 

From xargs man page:

Because Unix filenames can contain blanks and newlines, this default behaviour is often problematic; filenames containing blanks and/or newlines are incorrectly processed by xargs. In these situations it is better to use the -0 option, which prevents such problems. When using this option you will need to ensure that the program which produces the input for xargs also uses a null character as a separator.

From grep man page:

 -Z, --null 

Output a zero byte (the ASCII NUL character) instead of the character that normally follows a file name. For example, grep -lZ outputs a zero byte after each file name instead of the usual newline. This option makes the output unambiguous, even in the presence of file names containing unusual characters like newlines. This option can be used with commands like find -print0, perl -0, sort -z, and xargs -0 to process arbitrary file names, even those that contain newline characters.