Re: A little bash/perl programming help?

On Thu, 27 Sep 2007 20:26:51 +0000, Stuart Miller wrote:

"Ivan Marsh" <annoyed@xxxxxxx> wrote in message
news:pan.2007.09.27.16.30.11.967926@xxxxxxxxxx
Okay, I admit it, I'm stumped.

I'm trying to write a script to parse out text files into 80 charter
line lengths with column numbering over each line and I just can't seem
to get the logic straight in my head. The desired output would look
(something) like:

123456789012345678901234567890123456789012345678901234567890 All work
and no play makes jack a dull boy. All work and no

123456789012345678901234567
play makes jack a dull boy.

Putting each 80 character section on a separate line with the column
numbers over it.

Anyone have anything that does something like this? I was trying to
write it in bash but got more confused the more I worked on it. A perl
example would work too.

(For the record: No, it's not homework. I'm trying to write a script I
just lost when a very old server died.)

-thx


--
I told you this was going to happen.

It looks to me like a perl script for this would be very easy to write.
I would need to know the format of the input text file, delimiters,
etc.and what form the output would take - console, text file, report
type file. Logic would need to check line length, if > 80 take left 80
characters, process & print; if < 80 and not end of file read &
concatenate next line, and loop.
I would use 2 lines for the column numbers, as 1 2
1234567890123
and find a good monospace font - courier usually works ok

Depending on the complexity of the input and output section, I see it
taking 2-3 hours to write.
That means that a professional programmer can do in in 20 minutes....

Stuart

Ivan, here's some (modified) code from a vigenere cipher shell script I
wrote. It's got some limitations, specifically the notion that you read
an entire text file into a variable, kind of a no-no in bash scripting
IIRC. I've tested it with text files up to about 15,000 characters on a
PIII, 512MB machine running Fedora 7 and it works, but you may want to
try a "while read line ..." method of reading the lines from the file one
at a time(this didn't work for me in the cipher problem as I couldn't
keep a one to one correspondence with the key text, but should not be a
problem for your application). Failing that, enclosing the $filename in
quotes, I think, will preserve the spaces and newlines from the original
file, ie,

line=`cat "$filename"`

Also, you could create a larger loop to run each "while" statement again
if you want the column numbers atop each line, or just the second "while"
if you just want the lines.

*******Begin Code***********

j=0
k=0
while [ $j -le 80]
do
k=`expr $j % 10` # Resets column header to "0" every 10 characters
printf $k
k=$((k + 1))
j=$((j + 1))
done

echo # prints the 'newline' to start the text below

line=`cat $filename` # Reads the file into variable $line
while [ $i -le 80 ]
do
substring=${line:$i:1}
printf $substring
i=$((i + 1))
done

echo # Another newline, start again.

******End Code***********

Rich ... novice shell scripter, but learning!

.

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