Shell Programming and Scripting

I don't think it's removed, since everything that happens within arithmetic expansion is treated as if it's double-quoted. It's just that whitespace is allowed between operators and operands within $((...)).

Regards,
Alister

good night my friends!!! thank you sooo much for all you've done for me!!
I'll be here tomorrow again because I think that I will have another question!!!
bye bye and thaaaanks!!!!

---------- Post updated at 06:34 PM ---------- Previous update was at 06:31 PM ----------

good night my friends!!! Thank you sooo much for all you've done for me!!!
I'll be here tomorrow again, because I think that I will have another question!!!
bye byeee

---------- Post updated at 06:34 PM ---------- Previous update was at 06:34 PM ----------

haha two times

---------- Post updated at 06:36 PM ---------- Previous update was at 06:34 PM ----------

hahaha two times!!

---------- Post updated 04-14-11 at 09:48 AM ---------- Previous update was 04-13-11 at 06:36 PM ----------

Hello again!!!
Can anyone tell me please what is the job of the command:

Code:

tr -cs "[:alpha:]" "[\n*]" < inputfile

I read sth on the web but I don't get it!

Contiguous non-alphabetic characters are replaced with a single newline.

oookaaaay!!!
now I have a different problem.I want to generate a number from 1 to 10 and I have written this:

Code:

x=$RANDOM
y=$RANDOM
num=`exp \($x32768+$y\) % 10`

and I have errors...

---------- Post updated at 11:59 AM ---------- Previous update was at 11:57 AM ----------

Code:

num=`expr \($x*32768+$y\) % 10`

this is what I have written in reality ...

---------- Post updated at 12:01 PM ---------- Previous update was at 11:59 AM ----------

error:
expr: non-integer argument

What is your system? What is your shell? Unless you're stuck using a really old shell there's way better ways to handle numbers than expr.

expr is thorny. It expects each individual thing to be a seperate argument, like "1" "+" "2". So (1+2)/stuff is out, that jams it all into one argument. So is "1+2". 1 + 2 works because of the spaces.

expr has the % operator for remainder or modulus, 1 % 10 is 1, 9 % 10 is 9, 10 % 10 is 0, 11 % 10 is 1, etc. So you can do $RANDOM % 10 to get a number from 0-9, and add 1 to it to get a number from 1-10.

VAL=`expr $RANDOM % 10 + 1`

I use th bash shell... ok... if I want to generate a number for example from 1 to 100000, then why these commands:

Code:

x=$RANDOM
y=$RANDOM
num=`expr \($x * 32768 + $y\) % 100000

have the error:
expr: syntax error??
I think that I wrote them correctly... according to the colors...

Indeed. And the fact that many components of the expr(1) syntax are shell metacharacters compounds the hassles, since one can't simply stuff the entire expression within strong quotes.

Regards,
Alister