I wanted to download some tuts on aircrack by wget and I failed:

wget -r 2 http://www.aircrack-ng.org/doku.php\?id=tutorial\&DokuWiki=78e8249415a9ce232228ed8f9f02b9dd 
--2011-10-06 14:16:11--  http://2/
Resolving 2...
Connecting to 2||:80... failed: Invalid argument.
--2011-10-06 14:16:11--  http://www.aircrack-ng.org/doku.php?id=tutorial&DokuWiki=78e8249415a9ce232228ed8f9f02b9dd
Resolving www.aircrack-ng.org..., 2001:41d0:1:1b00:213:186:33:2
Connecting to www.aircrack-ng.org||:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [text/html]
www.aircrack-ng.org/doku.php?id=tutorial&DokuWiki=78e8249415a9ce232228ed8f9f02b9dd: Invalid argument

Cannot write to `www.aircrack-ng.org/doku.php?id=tutorial&DokuWiki=78e8249415a9ce232228ed8f9f02b9dd' (Invalid argument).

Do you know how to fix this problem ?

  • I can't reproduce the problem, but you should remove the 2 after -r (that option doesn't take an argument). Oct 6, 2011 at 12:30

3 Answers 3


This is probably the filesystem you're downloading to not allowing a filename with "?" in it. Note that the error is "Cannot write".

You can use the --restrict-file-names=windows option to escape names for compatibility with FAT filesystems. (Note that the non-reversible additional %-encoding done by wget is not actually correct vs. web architecture, but you probably don't care.)

You could also use -O <filename> to specify a particular filename if you were downloading only one file.

  • --restrict... solved this for me, using Ubuntu bash on windows 10
    – chwi
    Aug 31, 2018 at 8:13

The & also commonly causes problems. Try putting the whole url in quotes.


As suggested by pjc50, please put the URL within quotes when you have special characters in it. Therefore, you should try:

wget -r 2 'http://www.aircrack-ng.org/doku.php?id=tutorial&DokuWiki=78e8249415a9ce232228ed8f9f02b9dd'

When you do not use quotes, the shell, on encountering a &, assumes you want to run the wget job in background.

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