Sponsored Content
Top Forums Shell Programming and Scripting Condition test ( [[ ]] ) doubt Post 302132331 by thambi on Thursday 16th of August 2007 11:53:04 AM
Old 08-16-2007
Question Condition test ( [[ ]] ) doubt

Hi ,

I have a doubt on condition test ( [[ ]] ). Pls refer blow program.

#!/bin/ksh
TEMP=
if [ -n $TEMP ];then
echo $TEMP
else
print 'invalid option'
fi

Above script's TEMP variable has no value so it gives "invalid option" as output. But I got an error before priting the string .

Result :

./test.ksh[3]: test: argument expected
invalid option


#!/bin/ksh
TEMP=
if [[ -n $TEMP ]];then
echo $TEMP
else
print 'invalid option'
fi

Result:
invalid option

After I tried IF conditon with condition test [[ ]] , I did not see the error (./test.ksh[3]: test: argument expected ).
Why I don't see the error now?.
How Condition test [[ ]] is actually working ?.
How [[ ]] differ from normal if condition?


Regards,
Thambi
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

need help with test condition in shell script

I'm new to scripting and I need help with a bourn shell script. What i'm trying to do is a test condition where "if the time is within 2 hours, it's true" and so on. The time is in the following format DATE=`/bin/date +"%Y%m%d%H%S"` for example, 20060907152000. So, what the script first... (9 Replies)
Discussion started by: pieman8080
9 Replies

2. Shell Programming and Scripting

test and if condition

Guys look at this: i have to write a script that takes a file as an argument. The script should be able to determine what permissions the owner, group and everybody has for the file passed in. The output should be displayed similar to this. READ WRITE EXECUTE OWNER LEE.BALLANCORE YES YES NO... (9 Replies)
Discussion started by: ciroredz
9 Replies

3. UNIX for Dummies Questions & Answers

Condition test

Hi there, When I try to do a condition on test: $ str1=abcd $ test $str1 $ echo $? 0 Is there anyway to display the answer to be 'TRUE' or 'YES'? rather than 0? If so, how can I do it without using awk or sed. (2 Replies)
Discussion started by: felixwhoals
2 Replies

4. Shell Programming and Scripting

IF condition doubt

Hi i found the following code in a date calculation script. if ((!(year%100))); then ((!(year%400))) && leap=1 else ((!(year%4))) && leap=1 fi I have not find such an use of if statement till now. As for my knowledge this is the syntax of if statement if then ... (1 Reply)
Discussion started by: ravi raj kumar
1 Replies

5. Shell Programming and Scripting

Test condition

Hello, what is the better and correct way to perform a comparison: I have been using the following with no problems: if ] then .... fi I have seen this also used : if then .... fi When I try : if then .... fi I get an error like .... the test condition expects a... (4 Replies)
Discussion started by: gio001
4 Replies

6. Shell Programming and Scripting

test condition

Hi there, I tried to search for this almost everywhere, but didnt get any proper information on it. What is the difference between ] Some of the code works when I have only single condition i.e. ] && $dothis1 || $dothis2 But if i try to include another testcondition to the... (1 Reply)
Discussion started by: tostay2003
1 Replies

7. Shell Programming and Scripting

How to check weather a string is like test* or test* ot *test* in if condition

How to check weather a string is like test* or test* ot *test* in if condition (5 Replies)
Discussion started by: johnjerome
5 Replies

8. UNIX for Dummies Questions & Answers

Simple negated test condition

Without grep, I'd like to make a test condition so that any a word that does not have the successive letters car in it will be echoed. for example, bluecar will contain "car" so it will show up as a no var=bluecar $ echo $var|if ]; then echo "yes";fi yes this variable contains "car" so I... (5 Replies)
Discussion started by: newbie2010
5 Replies

9. Shell Programming and Scripting

For loop/while condition - doubt

hi., As we know that using for-loop or while condition, we can only process one by one sequentially, but , lets say this example : 1. under the folder "logs" there are 1000 files 2. each file has one record or line 3. have to perform atleast 7 queries per 3 seconds ,for instance ... (3 Replies)
Discussion started by: alnhk
3 Replies

10. UNIX for Beginners Questions & Answers

Test a condition for n times and take action

i have to test a condition for n times and if its value is greater than one each time for continuous 5 iterations it will take action My Approach run the same command 5 times in for loop and divert the output to a file and then read the values from file and use if else if and take action ... (1 Reply)
Discussion started by: abhaydas
1 Replies
SQL::Translator::Parser::SQLite(3pm)			User Contributed Perl Documentation		      SQL::Translator::Parser::SQLite(3pm)

NAME
SQL::Translator::Parser::SQLite - parser for SQLite SYNOPSIS
use SQL::Translator; use SQL::Translator::Parser::SQLite; my $translator = SQL::Translator->new; $translator->parser("SQL::Translator::Parser::SQLite"); DESCRIPTION
This is a grammar for parsing CREATE statements for SQLite as described here: http://www.sqlite.org/lang.html CREATE INDEX sql-statement ::= CREATE [TEMP | TEMPORARY] [UNIQUE] INDEX index-name ON [database-name .] table-name ( column-name [, column-name]* ) [ ON CONFLICT conflict-algorithm ] column-name ::= name [ ASC | DESC ] CREATE TABLE sql-command ::= CREATE [TEMP | TEMPORARY] TABLE table-name ( column-def [, column-def]* [, constraint]* ) sql-command ::= CREATE [TEMP | TEMPORARY] TABLE table-name AS select-statement column-def ::= name [type] [[CONSTRAINT name] column-constraint]* type ::= typename | typename ( number ) | typename ( number , number ) column-constraint ::= NOT NULL [ conflict-clause ] | PRIMARY KEY [sort-order] [ conflict-clause ] | UNIQUE [ conflict-clause ] | CHECK ( expr ) [ conflict-clause ] | DEFAULT value constraint ::= PRIMARY KEY ( name [, name]* ) [ conflict-clause ]| UNIQUE ( name [, name]* ) [ conflict-clause ] | CHECK ( expr ) [ conflict-clause ] conflict-clause ::= ON CONFLICT conflict-algorithm CREATE TRIGGER sql-statement ::= CREATE [TEMP | TEMPORARY] TRIGGER trigger-name [ BEFORE | AFTER ] database-event ON [database-name .] table-name trigger-action sql-statement ::= CREATE [TEMP | TEMPORARY] TRIGGER trigger-name INSTEAD OF database-event ON [database-name .] view-name trigger-action database-event ::= DELETE | INSERT | UPDATE | UPDATE OF column-list trigger-action ::= [ FOR EACH ROW | FOR EACH STATEMENT ] [ WHEN expression ] BEGIN trigger-step ; [ trigger-step ; ]* END trigger-step ::= update-statement | insert-statement | delete-statement | select-statement CREATE VIEW sql-command ::= CREATE [TEMP | TEMPORARY] VIEW view-name AS select-statement ON CONFLICT clause conflict-clause ::= ON CONFLICT conflict-algorithm conflict-algorithm ::= ROLLBACK | ABORT | FAIL | IGNORE | REPLACE expression expr ::= expr binary-op expr | expr like-op expr | unary-op expr | ( expr ) | column-name | table-name . column-name | database-name . table-name . column-name | literal-value | function-name ( expr-list | * ) | expr (+) | expr ISNULL | expr NOTNULL | expr [NOT] BETWEEN expr AND expr | expr [NOT] IN ( value-list ) | expr [NOT] IN ( select-statement ) | ( select-statement ) | CASE [expr] ( WHEN expr THEN expr )+ [ELSE expr] END like-op::= LIKE | GLOB | NOT LIKE | NOT GLOB AUTHOR
Ken Youens-Clark <kclark@cpan.org>. SEE ALSO
perl(1), Parse::RecDescent, SQL::Translator::Schema. perl v5.14.2 2012-01-18 SQL::Translator::Parser::SQLite(3pm)
All times are GMT -4. The time now is 04:43 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy