tr problem

Les Mikesell lesmikesell at gmail.com
Fri Jun 13 13:10:51 UTC 2008


Gene Heskett wrote:
>> Man pages generally never mention the things the shell does to a command
>> line before starting the program.  This will include expanding variables
>> and wildcard filenames, redirecting I/O, and other things triggered by
>> shell metacharacters.  In this case tr doesn't particularly need the
>> quotes, but if you don't use them the shell will parse and remove the \
>> characters (treating them as quotes for the following character in its
>> own parsing).  These details are the same for every command you type (or
>> script) and not repeated in every man page.
>>
> I got it working now, but once its done, I won't need it again till 3 years down 
> the log, and will have forgotten it again.  Thanks Les.

But you use the shell every day and it parses/processes every command 
you type.  It's worth a bit of time learning what to expect from it at 
least in terms of variable and wildcard substitions, i/o redirection, 
quote processing and a few other things.  And it helps to know that when 
looking at any other program's man page.

-- 
   Les Mikesell
    lesmikesell at gmail.com




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