script problem

Thread Tools Search this Thread
Top Forums Shell Programming and Scripting script problem
# 1  
Old 09-11-2002
script problem

Hi All

In a script (ksh), I want a user to enter 4 characters, these can be a mix of letters (uppercase and lowercase) and numbers.

In this example $var represents what the user has entered.

eg $var can be A9xZ, 3DDL, bbHp .........etc

I need to check that the user has only entered characters so I added the following code:

# Check for invalid characters
echo "$var" | grep [^a-zA-Z0-9] >/dev/null
if [ $? -eq 0 ]
echo "$var is not valid."

This appears to work ok unless the user enters a wildcard character.

For example if the user enters bin*, the script expands the * and makes $var equal to all files in the current directory which start with bin.

So $var is "bin bindir binary"

My question is how can I process $var literally as "bin*" in the above grep statement?

Thanks for your help
# 2  
Old 09-11-2002
try grep [^a-zA-Z0-9 add your list of metacharictures here]
# 3  
Old 09-11-2002
Hello Helen,

echo "$var" | grep [^a-zA-Z0-9] >/dev/null
will return a 0 if $var is "bin*" because the grep is only serching for alphabetic characters and numbers.

Plus if you do: echo "$var"
This will return: bin*

However, if you do(without quotes): echo $var
This will return: bin binary ....

If you do want * to be a valid character you can put a (backslash) \ before it in the grep statement. This turns off any special meanings of such characters.

Hope this answers your question.
# 4  
Old 09-11-2002
You should forget about grep anyway. ksh can do this all by itself without invoking an external program. Try:
if [[ $var = +([a-zA-Z0-9]) ]] ; then
        echo $var is ok
        echo $var is an error

Note that you must use the double bracket not the single bracket.
# 5  
Old 09-16-2002

Thanks for all your help on this Smilie
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Problem in calling a script inside a script

Hi team, I have a script in different folder. Now i want to call that script and execute that script from that path alone. My code is #!/bin/bash wname=yahoo PATH='/opt/IBM' wac=`/usr/bin/ls $PATH | /usr/bin/grep "$wname"` STOP=`/usr/bin/find $PATH/$wac -type f -name ""`... (8 Replies)
Discussion started by: natraj005
8 Replies

2. Shell Programming and Scripting

Shell script newbie, what is problem with my script?

Hello, Ubuntu server 11.10 can anybody help what is problem with my shell script? #!/bin/bash #script to find out currently logged on user is root or not. if ] then echo "You are super" else echo "You are awesome!" fi When I run script, I get following output ./uid: line 3: I... (4 Replies)
Discussion started by: kaustubh
4 Replies

3. Shell Programming and Scripting

Problem while calling a script within a script

Hi , I have moduled my scripts in three scripts . From First script i am calling second and from second i am calling third for some check . Problem is with the third script call. ---In second script EXP ='test.\abc.\Server.*abc.xml.*' pid=$($HOME/bin/checkpid $EXP) --Third... (2 Replies)
Discussion started by: amrishn
2 Replies

4. Shell Programming and Scripting

Problem running a program/script in the background from a script

Hi all, I have a script that calls another program/script, xxx, to run in the background. Supposedly this program at most should finish within five (5) minutes so after five (5) minutes, I run some other steps to run the script into completion. My problem is sometimes the program takes... (5 Replies)
Discussion started by: newbie_01
5 Replies

5. Shell Programming and Scripting

Problem with a script

Hi everyone, I got a problem with a script. What it's supposed to do is: to take as arguments a directory name <dir> and a dimension (in byte) <dim>; if <dir> exists, to write name and dimension of every regular file within it that sizes lesser than <dim> in regFileList. Nothing happens... (10 Replies)
Discussion started by: Luke Bonham
10 Replies

6. UNIX for Dummies Questions & Answers

Problem with script

Hello All. I have a script that is suppossed to start up a daemon but when executed, simply hangs. Could you please take a look and let me know where the problem might be? TIA ################################################################### # # SCRIPT: # Bring up the Domain... (6 Replies)
Discussion started by: grin1dan
6 Replies

7. Shell Programming and Scripting

call shell script from perl cgi script problem

hi,, i have perl scipt with line : system('./ $t $d $m'); in shell scipt i have the line: echo $1 its not printing value of $t that i hav passed..y is it so..i am running it from apache web server (2 Replies)
Discussion started by: raksha.s
2 Replies

8. Shell Programming and Scripting

ssh script problem problem

Hi Please help me with the following problem with my script. The following block of code is not repeating in the while loop and exiting after searching for first message. input_file ========== host001-01 host001-02 2008-07-23 13:02:04,651 ConnectionFactory - Setting session state... (2 Replies)
Discussion started by: pcjandyala
2 Replies

9. Shell Programming and Scripting

Help. Script problem

hey guys. i have a bunch of programs in a script that needs to run as root and the rest as another user, we'll call him gabriel. now, in this script, i want to run the first few lines as root. now, how do i, after running as root, tell the script to run the remaining lines as the user gabriel?... (3 Replies)
Discussion started by: Terrible
3 Replies

10. UNIX for Dummies Questions & Answers

Problem starting a script from a 'main'-script

Please Help! :o I have a main script (ksh) where another script is called (convert_picture). Normally this works ok, but since some changes has been made on the unix-server (I dont know what :( ) suddenly it doesnt work anymore: i get an error message: ksh: convert_picture not found. I am... (3 Replies)
Discussion started by: Rakker
3 Replies
Login or Register to Ask a Question

Featured Tech Videos