Timothy Bolz wrote:
> Is there a bash commnad similiar to scanf in C or would you have to
> use C for this?
There is read. Read separates an input line into words, but the
shell generally doesn't distinguish between numbers and strings.
$ read a b
3 4
$ echo $a
3
$ echo $b
4
> Is there a way to print line #x ?
Yes. I'd use sed.
$ sed -n 12p /etc/passwd
operator:x:11:0:operator:/root:
> Is there a comand which does decimal math?
Yes. The command is "expr".
$ expr 3 + 4
7
$ expr 3 \* 4 # note: must quote '*'
12
$ expr 3 + 4 \* 5
23
$ expr \( 3 + 4 \) \* 5 # also quote '()'
35
You can combine that with shell variables and command interpolation
(i.e., commands in backticks) like this.
$ x=3
$ y=4
$ z="`expr $x + $y`"
$ echo $z
7
Also, you can use bc and dc for more complex stuff.
$echo 3 + 4 | bc
7
$ echo 3 4 + p | dc
7
So you're writing a program that reads numeric input, does arithmetic
calculations, and prints selected lines from a file. You can do all
that in bash, but it might be time to look at a real scripting
language such as Python or Perl.
--
Bob Miller K<bob>
kbobsoft software consulting
http://kbobsoft.com [EMAIL PROTECTED]
