[Nottingham] "unescaping" the wildcard character for xargs

[Mike Cardwell]

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On 19/06/12 12:30, Rory Holland wrote:

> Let's say I have a command which outputs line-delimited filenames
> with wildcards in them.
> 
> For example:
> 
> /home/alice/* /home/bob/* /home/eve/*
> 
> I'm trying to cat these files, but using the following doesn't
> work
> 
> <command> | xargs cat
> 
> This is because the * character is being interpreted literally, so
> I get the following error on each line:
> 
> cat: /home/alice/* : no such file or directory.
> 
> Nothing in man xargs seems to help. What can I do?

The problem is, it's the shell which interprets and translates the
"*", not cat. Under normal circumstances, if you were to run the
command: "cat *", then the "*" is translated by the shell before cat
even sees the argument list.

I don't know how you can compensate for this in xargs, and I'm sure
there's a better way than this, but I'd just do it like this:

<command> | awk {'print "cat "$1'} | sh

As long as the output of <command> is really as simple as
"/home/user/*" and wont contain odd characters like spaces or
backslashes etc, then you'll be safe, otherwise you'll have to
consider properly escaping things.

- -- 
Mike Cardwell  https://grepular.com/     http://cardwellit.com/
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