Re: Spaces in File name Handling

[alupu]

Hi Paul,

Thank you very much for your comments and clarifications.

Again, at your leisure, your words on the following will be highly appreciated.

> Alex says (excerpts):
When the shell hands over an argument ($TMP) to “echo” it removes the LFs ...
...
Does this go all the way back to the old “Doug McIlroy” philosophy on echo 
described in “The Unix Programming Environment” - Using the Shell, by BWK and 
RP?

>> Paul replies (excerpts):
... but if [ls] notices that it is writing to a pipe, as is the case for 
`command substitution`, then it writes just one name per line.
... 
> # In a directory with three files, "A", "B C" and this "T" procedure:
> TMP=`ls -A`
> echo $TMP > E
At this point, $IFS still has the default value - space, tab, and
newline - so echo sees four arguments ("A", "B", "C", "T").
...
Unquoted variable expansions get split at $IFS delimiters in either case. 

-- Alex (live):

Not really, "echo $TMP" appears to have the LFs stripped (staying with the 
original example - with $IFS at default, before being subsequently modified to 
accept only LFs).
# Same old directory, three files, “A”, “B C” and this “T” procedure:
TMP=`ls -A`
echo $TMP > E
echo "$TMP" > F

cat E:
A B C T

cat F (surprise, surprise):
A
B C
T

Not surprisingly now, for completeness, dump E:
41 20 42 20 43 20 54 0a

and dump F:
41 0a 42 20 43 0a 54 0a

It appears that if I _quote_ the argument to echo, the shell will finally 
behave as expected (by the uninitiated) and echo will show the naked truth 
(splits and all).  Had I known that (or seen it mentioned somewhere) I _may_ 
have had the chance to figure out the $IFS business on my own and avoid a lot 
of sleepless nights and weight loss and, what's more important, save you the 
aggravation of dealing with me!
Oh well, when all your life you're told to 'echo $PATH' (and not 'echo 
"$PATH"') you miss the bigger picture at times.

So I'm taking the liberty of again asking for your thoughts on the preceding 
e-mail's last question (Doug's whimsical take on "echo and LF" - full text at 
the beginning of this letter).

Many thanks and best wishes,
-- Alex