Sponsored Content
Full Discussion: Null handling in scripts
Top Forums Shell Programming and Scripting Null handling in scripts Post 60671 by zazzybob on Thursday 20th of January 2005 10:02:29 AM
Old 01-20-2005
Or for true "nulls" and unset variables, etc..

[ -z "$i" ] && echo "nothing here"

Cheers
ZB
 

10 More Discussions You Might Find Interesting

1. UNIX for Advanced & Expert Users

Error Handling in Korn Shell scripts

Hi, I am using few ISQL statements to update and delete from a few tables in sybase, now i want to roll back the transaction when any of the statements fail.How i can i capture these errors in the shell scripts.Please advise. Thanks, Gopi (4 Replies)
Discussion started by: bhgopi
4 Replies

2. Shell Programming and Scripting

Handling null input...

Ok, so when a user inputs nothing, simply pressing enter when prompted for a phone number, I get a "./addrbkfct.sh: test: argument expected" error message. I have the following function: addNumber(){ echo "Phone number: \c"; read number; echo $number; if ;... (2 Replies)
Discussion started by: DrRo183
2 Replies

3. UNIX for Dummies Questions & Answers

Handling Errors in Shell Scripts

I have a shell script, which calls a load script to load a database. How can i handle errors in Unix(similar to 'error level' in Batch scripts)? I am trying to use 'mailx' to send a Success/failure message based on the error level returned by the load script. I have already used an error log... (2 Replies)
Discussion started by: sarsani
2 Replies

4. Shell Programming and Scripting

Null Character Handling

Hi All, I have a problem with Null values while reading line by line from a text file. I wrote a shell script to read set of file names from a text file line by line, and zipping the each individual file and copying those zip files into some separate directory, and removing the original file... (3 Replies)
Discussion started by: npk2210
3 Replies

5. Shell Programming and Scripting

handling null values in files

Hi , I have a script where i will remove header and trailer record and ftp to another server. I'm using the code: latestfilename=`ls filename_* | tail -1` echo "Latest filename = $latestfilename" sed '1d;$d' $latestfilename > a.ftpedfile I have an issue if input data is having null... (1 Reply)
Discussion started by: ammu
1 Replies

6. Shell Programming and Scripting

Advanced error handling in shell scripts

Hi all I've got a question regarding error handling in shell scripts. My background is mainly object oriented programming languages, but for a year or so I've been doing more and more (bash) shell scripting (which I quite enjoy by the way). To handle errors in my scripts I... (3 Replies)
Discussion started by: script_man
3 Replies

7. Shell Programming and Scripting

Null Handling in Until loop. . .loop won't stop

Hi Im running this script, which is supposed to find the max value build some tables and then stop running once all the tables are built. Thing is , it keeps assigning a null value to $h and then $g is null so it keep building tables i.e. testupdateNUL. How can I stop this? Here is what I have: ... (4 Replies)
Discussion started by: brandono66
4 Replies

8. Shell Programming and Scripting

Insert string 'NULL' where there is a null value

I have an input file having 7 fields delimited by , eg : 1,ABC,hg,1,2,34,3 2,hj,YU,2,3,4, 3,JU,kl,4,5,7, 4,JK,KJ,3,56,4,5 The seventh field here in some lines is empty, whereas the other lines there is a value. How do I insert string NULL at this location (7th loc) for these lines where... (8 Replies)
Discussion started by: zilch
8 Replies

9. Shell Programming and Scripting

Handling null Integer/string variables

I kind of found out the hard way that I am not able to manipulate the null value, the long silence that happens when there is no value returned. I am looking for PIDs, and when there is no PID return, I wanted to handle this special scenario. Here is my script. #!/bin/bash LAN_VARIABLE=... (7 Replies)
Discussion started by: lan123
7 Replies

10. Shell Programming and Scripting

Handling scripts in two different servers

Hi , My Script work as below 1- On server 1 execute script1.sh , through this script one parameter file is generated as file.txt this is to transfer on server 2 2- After reaching on server2 other shell script script2.sh execute using parameter file file.txt This generate file... (1 Reply)
Discussion started by: kaushik02018
1 Replies
unset(n)						       Tcl Built-In Commands							  unset(n)

__________________________________________________________________________________________________________________________________________________

NAME
unset - Delete variables SYNOPSIS
unset ?-nocomplain? ?--? ?name name name ...? _________________________________________________________________ DESCRIPTION
This command removes one or more variables. Each name is a variable name, specified in any of the ways acceptable to the set command. If a name refers to an element of an array then that element is removed without affecting the rest of the array. If a name consists of an array name with no parenthesized index, then the entire array is deleted. The unset command returns an empty string as result. If -nocom- plain is specified as the first argument, any possible errors are suppressed. The option may not be abbreviated, in order to disambiguate it from possible variable names. The option -- indicates the end of the options, and should be used if you wish to remove a variable with the same name as any of the options. If an error occurs, any variables after the named one causing the error are not deleted. An error can occur when the named variable does not exist, or the name refers to an array element but the variable is a scalar, or the name refers to a variable in a non-existent namespace. EXAMPLE
Create an array containing a mapping from some numbers to their squares and remove the array elements for non-prime numbers: array set squares { 1 1 6 36 2 4 7 49 3 9 8 64 4 16 9 81 5 25 10 100 } puts "The squares are:" parray squares unset squares(1) squares(4) squares(6) unset squares(8) squares(9) squares(10) puts "The prime squares are:" parray squares SEE ALSO
set(n), trace(n), upvar(n) KEYWORDS
remove, variable Tcl 8.4 unset(n)
All times are GMT -4. The time now is 01:37 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy