I have the necessity to use this command:
cat file1 | grep $A | grep $B
where sometime A and, or, B are not set.
For example:
I set A=@
never defined or set B
The above command send a cat error.
Any idea?
Thanks.
Giovanni (1 Reply)
hi forum
i beginning with script and i want test un null variable in a schell
i just don t know the syntax here is a litle example
y=test
echo $y
unset y
echo $y (so here Y = Null)
if Y=Null
then
echo "y is null"
exit
fi (1 Reply)
Hi,
I have to check whether an argument say $ARGV is not null in an if operator. Please let me know the operator. It would be great if you write a psuedo code.
Thanks in advance
Ammu (4 Replies)
korn shell
If
then
update_smartcare_user_password "$u_id"
else
echo "Not a database user"
fi
i get this error
Syntax error at line *** : `then' is not expected.
what should i do.
I want to check whether $a is null or not. (2 Replies)
Hi all, I have a stupid question on NULL and zero(0).
In a script I've been working with, one of the lines is:
if &&
then
The problem I seem to have is when $Current_csm2 is null, this if block is not triggered, and I don't get why because I was under the impression that NULL!=0
Can... (7 Replies)
Hello, Unix-forums!
My problem:
read -p "Enter any number, please" number
sleep 1
echo $number | tr -d 0-9
test -z $number && echo "Thank you" || echo "This is not a number"Test always displays "This is not a number". It doesn't matter if I entered a or 1.
But if I order
echo... (2 Replies)
i have this code
for i in `cat sql_output.txt`
do
-- some script commands
done
sql_output.txt has 1 column with employee_ids
If the sql_output.txt is null then the do loop should not execute.
How can i implement this.
for i in `cat sql_output.txt`
If i is null or empty
then ... (5 Replies)
Guys,
Please help me on the below
sample.cfg
var=NULL
sample.sh
#!/bin/sh
. /sample.cfg
if ;then
1 st command here
else
2 nd command here
fi (3 Replies)
DELETE=`cat $logfile1 | egrep -i "Delete" | sed 's/ */ /g' | cut -d" " -f2`
INSERT=`cat $logfile1 | egrep -i "Insert" | sed 's/ */ /g' | cut -d" " -f2`
UPDATE=`cat $logfile1 | egrep -i "Update" | sed 's/ */ /g' | cut -d" " -f2`
I need soming like below:
if value is null... (8 Replies)
Discussion started by: Veera_V
8 Replies
LEARN ABOUT DEBIAN
envstore
ENVSTORE(1) BSD General Commands Manual ENVSTORE(1)NAME
envstore -- save and restore environment variables
SYNOPSIS
envstore command [args ...]
DESCRIPTION
envstore can save and restore environment variables, thus transferring them between different shells.
command must be one of
clear
Forget all stored variables
eval
Produce shell code for evaluation, restoring all saved variables
list
List saved variables in better readable format
save variable [value]
Save variable either with its current shell value or with value
rm variable
Remove variable from store
Note: Only the first character of command is checked, so envstore e instead of envstore eval, envstore c for envstore clear, etc., are also
valid.
ENVIRONMENT
ENVSTORE_FILE The file in which the environment parameters are stored, /tmp/envstore-EUID by default,
LIMITATIONS
Variable names or values must not contain null bytes or newlines.
Due to limitations imposed by most shells, it is not possible to save parameters containing more than one consecutive whitespace. envstore
will save and display them correctly, but unless you do IFS trickery, your shell will not be able to load them.
The current maximum length (in bytes) is 255 bytes for the variable name and 1023 bytes for its content.
AUTHOR
envstore was written by Daniel Friesel <derf@derf.homelinux.org>.
Original idea and script by Maximilian Gass <mxey@ghosthacking.net>.
SEE ALSO envify(1)BSD December 1, 2009 BSD