Variables in shell script not working

[Carl Friis-Hansen]

Jef Driesen wrote:
> Karl Auer wrote:
>> On Sat, 2008-11-15 at 16:20 +0100, Jef Driesen wrote:
>>> This is indeed the problem! At first, I only had the sed command,
>>> which does accept a filename AND outputs to stdout. I simply didn't
>>> think about this difference when adding the dos2unix command.
>>>
>>> Is it possible to have the pipe command in the variable, without cat 
>>> interpreting both the pipe symbol "|" and the "dos2unix" as its
>>> argument?
>>>
>>> SOURCE="cat $FILENAME | dos2unix"
>> Yes, that will work fine - but it doesn't run sed, and the output goes
>> to stdout rather than being saved in the original file.
>>
>> This will convert the filename and (if the conversion worked) run it
>> through sed, sending the output to stdout:
>>
>>    FILENAME=$1
>>    dos2unix $FILENAME && cat $FILENAME | sed s/foo/bar/
>>
>> That's basically what Carl was saying, too.
>>
>> But what is it you actually want to achieve here? The above will send
>> the sedded output to stdout after unixifying the specified file, but the
>> sedded output will not be saved in the file.
> 
> What I want to achieve is process some data that is passed through stdin 
> or a filename. Which source is used depends on whether a filename is 
> passed on the commandline or not. That way I can run my script in two 
> ways (similar to how you can use sed):
> 
> ./myscript myfile
> myprogram | ./myscript
> 
> Because sometimes my input is stored in a file and sometimes it is the 
> output of another program.
> 
> The output should always go to stdout and when the script is used with a 
> filename, the original should not be modified. So that excludes running 
> dos2unix on it directly.

Your problem here is dos2unix, which does not appear to support support 
std input/output. When you want to use this utility, couldn't you take 
your input and store it in a temporary file and then use this temporary 
file in the same process as described before?

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