On Aug 2, 2007, at 9:40 PM, David Livesay wrote:
> On Aug 2, 2007, at 11:58 PM, John Baxter wrote:
>
>> As to your missing whitespace, you could try replacing the
>> echo $i
>> with
>> echo "$i"
>>
>> That has to be double-quotes--single quotes would cause your
>> output to be a series of lines containing the literal $i
>
> Keeping all the different quotes straight--single quotes, double
> quotes, backquotes--has to be one of the hardest things about
> learning shell scripting.
>
>> That should present the whole line to echo as a single argument,
>> and in that case echo won't mess with whitespace inside the
>> argument. With just $i, the $i is indeed the whole line, but echo
>> sees it as a series of arguments (word-like things), and emits
>> them with a space separating them.
>
> It's not what echo is doing to i; it's how for is interpreting the
> output of cat and putting it into i. When you pass a list to for,
> that list can be space-, tab- or return-delimited, or any
> combination thereof, so it sees each line as a list if it has
> spaces in it.
Compare these two:
$echo This is a test.
This is a test.
$echo "This is a test."
This is a test.
In the first, echo gets four "words"---in the second it gets one.
In the loop in your original message, echo has no idea about anything
named $i--it only knows what the system has given it--a bunch of
"words" when the quotes were absent vs a single "word" with the
quotes present (it doesn't see the quotes). Thus...
$i="This is a test."
$echo $i
This is a test.
$echo "$i"
This is a test.
(In all cases there INCLUDING the assignment, the leading $ on the
lines that have it is the shell prompt. So in the first one, the
command is
i = ....
)
Continuing...
$j="'Twas brillig, and the slithy toves"
$echo "$i" "$j"
This is a test. 'Twas brillig, and the
slithy toves
$echo "$i$j"
This is a test.'Twas brillig, and the
slithy toves
and even
$echo "$i $j"
This is a test. 'Twas brillig, and
the slithy toves
--John
|
