topic Re: Shell Puzzle in Operating System - HP-UX

Shell Puzzle

Dan Am — Wed, 06 Mar 2002 11:47:54 GMT

Hi All,
in our Unix-Class here, s'one came up with this idea:

touch " "
touch " "

So, now we have two files, each with only whitespaces in their name. How can we:
1) access each file selectively
2) make the whitespaces visible

ls -b does not do the trick, as whitespaces are not "non-printing" as such.

Anyone ever run into this ?

Regards
Dan

Re: Shell Puzzle

Peter Kloetgen — Wed, 06 Mar 2002 11:50:54 GMT

Hi,

if you call the files with the vi- command, it shows the file name in the left bottom corner marked with ""- characters.

filename " "

Allways stay on the bright side of life!

Peter

Re: Shell Puzzle

federico_3 — Wed, 06 Mar 2002 11:56:26 GMT

You should use the inode number that can be found with ls -i

Ciao
Federico

Re: Shell Puzzle

Peter Kloetgen — Wed, 06 Mar 2002 11:56:39 GMT

Hi,

sorry, i forgot to mention how to access the files:

ls -l " " in the directory or:

ls -l /path_to_file/" "

rm /path_to_file/" "
rm ./" "

Allways stay on the bright site of life!

Peter

Re: Shell Puzzle

Dan Am — Wed, 06 Mar 2002 12:05:51 GMT

Funny, the forum machine did not actually process this richt either:

The first filename is 4 Whitespaces.
The second is 1 Whitespace.

Which makes it kind of hard.
How do do I handle a file by Inode Number ?

Regrds
Dan

Re: Shell Puzzle

Steve Steel — Wed, 06 Mar 2002 12:08:27 GMT

Hi

try

ls -b|while read line
do
echo filename \"$line\"
done

Then you have the names neatly between brackets
and can use the data

Steve Steel

Re: Shell Puzzle

Vasudevan MV — Wed, 06 Mar 2002 12:10:37 GMT

Hi,

Do the following things & see its output. You can use backslash (\) for special characters like blank spaces etc.

touch " "

echo "hello" >> \

cat \ or vi \

Hope this helps

Vasu

Re: Shell Puzzle

Peter Kloetgen — Wed, 06 Mar 2002 12:14:51 GMT

Hi,

try this command:

cat/more /path_to_file/" "
cat/more /path_to_file/" "

or the same syntax with each command. You simply have to quote the space characters.
If you want to find out, how many space- characters are in the name, use the following command:

vi /path_to_file/" *"

Allways stay on the bright side of life!

Peter

Re: Shell Puzzle

H.Merijn Brand (procura — Wed, 06 Mar 2002 12:22:57 GMT

perl -e 'opendir D,".";for(grep/^ /,readdir D){print"rm [$_] ? ";scalar=~m/^[YyJj]/ and unlink$_}'

if you'd put that in a shell, you can arg it, like

# prm \ *

(UNTESTED)
#!/opt/perl/bin/perl

opendir D, ".";
my @files = grep { -f } readdir D;

for (@ARGV){
foreach my $f (@files) {
$f =~ m/$_/ or next;
print "rm [$_] ? ";
scalar =~ m/^[YyJj]/ and unlink $_;
}
}

Re: Shell Puzzle

Peter Kloetgen — Wed, 06 Mar 2002 12:54:57 GMT

Hi Dan,

sorry, typo in last posting of mine:

ls -l /path_to_files/" *"

--> lists all files beginnig with a space, you would get two entries

vi /path_to_files/" *"

--> would open all files beginning with a space, one after the other and show you the names with visible spaces

Then, when you know the number of spaces, you can quote the file name when using the needed commands:

cmd "number_of_spaces"
or
cmd " *"

Allways stay on the bright side of life!

Peter

Re: Shell Puzzle

Dan Am — Wed, 06 Mar 2002 16:14:39 GMT

hi guys,
thanks to you all. vi seems to be the only
"readymade" solution here. I have not tried the Perl thing. I'll let you know on that.
Thanks again.
Regards
Dan

Re: Shell Puzzle

Rodney Hills — Wed, 06 Mar 2002 16:21:19 GMT

If you think you might have a filename with spaces, then you can do the following to see them-

ls -1 | sed -e 's/ /?/g'

This will do a ls command a replace any spaces with "?", thus making them visible.

-- Rod Hills

Re: Shell Puzzle

Darrell Allen — Wed, 06 Mar 2002 16:35:47 GMT

Hi Dan,

To access the files, quote them: surround the appropriate number of spaces with "".

To list multiple files beginning with a space:
ls " "*

Note the asterik is following the quotes, not inside.

To make the spaces visible you could do:
ls " "* | tr " " .
The output would be:
.
....

To see what characters are in the file names:
ls | od -b
0000000 040 012 040 040 040 040 012
0000007

Note 012 is a newline which delimits filenames in this output.

Darrell

Re: Shell Puzzle

Frank Slootweg — Thu, 07 Mar 2002 14:19:02 GMT

[I hope that this comes out OK. When posting, 'something' seems to convert multiple spaces to a single one.]

Adding to the other responses:

Let's first make some files *with* a content:

echo one >' ' # One space.
echo four >' ' # Four spaces.

> 1) access each file selectively

General:

command './ ' # One space.
command './ ' # Four spaces.

I.e. for *example*:

$ cat './ ' # One space.
one
$ cat './ ' # Four spaces.
four
$

> 2) make the whitespaces visible

ls -1 | cat -e
$
$
[other filenames]
$