11-08-2011
while condition with trouble
Hello!
i have a llittle missunderstanding with a script and maybe you can explain where is the mistake.
in the first place a have this script that is working just fine
...
read -p "enter the name of the instance: " instance
while [ -z "$instance" -o -z "`cat /home/oracle/instanta | grep "$instance"`" ];
....
but if i change the second condition with -z "`grep "$instance" /home/oracle/instanta `" then the script will fail! i don't understand why because if a run both conditions in the comand line i get the same result!
the same happens with the first condition : if a change with -z "`echo "$instance`"" the script won't work
what is a little bit strange is that if i create the script with a decisional block, something like this :
if [ -z `echo $instance` ];
....
its working just fine!
i'm really confused
thank you all in advance!
10 More Discussions You Might Find Interesting
1. UNIX Desktop Questions & Answers
Hello,
The system reboots in single user mode
what command to use to bring the system up regularly??
I get
INIT: cannot create /var/adm/utmpx
Type control -d to proceede with a normal startup
or give root passwd for system maintaince.
either way i don't have a change and ... (1 Reply)
Discussion started by: awk
1 Replies
2. What is on Your Mind?
Welcome to "The trouble with...." with your host, ZazzyBob.
Todays offering - "The trouble with letting other people host your website"
I use a certain web hosting service, who shall of course remain nameless here.
They are running PHP 4.3.10
I decide to write a script to test their PHP... (6 Replies)
Discussion started by: zazzybob
6 Replies
3. UNIX for Dummies Questions & Answers
Hi all,
having read lots of posts about SU I don't quiet understand this :
I'm doing regular backups of my database (u betta do) and therefore use su - username -c "sqlscript special data_base" in a unixscript which is even using cron. (yep!)
Now I need some other script, still with this... (4 Replies)
Discussion started by: nulnul7
4 Replies
4. Shell Programming and Scripting
Hi,
In an If condition, how can I specify if the variable are less than 5 letters, echo “error”.
Something like this one:
echo –n “Your name please: “
read name
if ; then
Echo “Your name must be at least 5 letters length”
exit
fi
Thanks a lot… (6 Replies)
Discussion started by: TARFU
6 Replies
5. Solaris
I'm not sure where to post this but it's happening on a SunOS 5.8 server so I'll try here.
I've discovered some unexpected behavior when using tr.
For example:
echo a | tr
Z
echo b | tr
a
echo a | tr
B
echo a | tr
B
echo a | tr
A (8 Replies)
Discussion started by: Mike@Work
8 Replies
6. UNIX for Dummies Questions & Answers
Hi there, I'm new to unix-environments.
I'm richard, and i'm mostly a web-developer, under php. I've done work in unix env before, but never had my own.
Today, I've got debian 3.1 r4 from the official site, and i've attempted to install it twice.
I installed it initially as "Desktop... (0 Replies)
Discussion started by: izua
0 Replies
7. Programming
Hey, i am having a problem
First, i know java well and i have used C++ on occasion so i thought i would be able to deal with a class where they program in C. unfortunately i have hit some speed bumps that i am having problems.
Here is my problem:
I have a structure cache_t in the sample... (0 Replies)
Discussion started by: zephoid
0 Replies
8. HP-UX
Executed the following if conditions .. and got different results .
only (( )) gave correct o/p with all scenarios .
Can anybody please let me know what is the difference between and ] and ((condition)) when used with if condition.
And why each condition gave different result.
1.... (2 Replies)
Discussion started by: soumyabubun
2 Replies
9. Shell Programming and Scripting
hi,
I have some problems in my simple script about the redirect echo stdout command inside a condition. Why is the echo command inside the elif still execute in the else command
Here are my simple script
After check on the two diff output the echo stdout redirect is present in two diff... (3 Replies)
Discussion started by: jao_madn
3 Replies
10. Shell Programming and Scripting
HI
My doubt may be basic one but I need to get it clarified..
When i use "if" condition that checks for many AND, OR logical conditions
like
if ]; then
return 0
fi
Even the if condition fails it returns as zero.. Any clue..
But if i add else condition like
if ]; ... (2 Replies)
Discussion started by: Priya Amaresh
2 Replies