04-30-2008
Variable has value or not
How do I check whether a variable has a value or not. When I am reading a value into a variable, I want to check whether the variable has value or not. How do I null check the variable.
My Problem is I am reading an IP Address into a variable. When I press enter without entering any value, the variable won't have any value, now I want to check whether this variable has value in it or not.
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
This is what I tried:
vara=${varb}_count
(( vara += 1 ))
Thanks for help (4 Replies)
Discussion started by: pa3be
4 Replies
2. Shell Programming and Scripting
Hello,
i have another sed question.. I'm trying to do variable substition with sed and i'm running into a problem.
my var1 is a string constructed like this:
filename1 filerev1 filepath1
my var2 is another string constructed like this:
filename2 filerev2 filepath2
when i do... (2 Replies)
Discussion started by: alrinno
2 Replies
3. Shell Programming and Scripting
I want to instert Category:XXXXX into the 2. line
something like this should work, but I have somewhere the wrong sytanx. something with the linebreak goes wrong:
sed "2i\\${n}Category:$cat\n"
Sample:
Titel Blahh Blahh abllk sdhsd sjdhf
Blahh Blah Blahh
Blahh
Should look like... (2 Replies)
Discussion started by: lowmaster
2 Replies
4. Shell Programming and Scripting
Hi all,
I have a variable say var1 (output from somewhere, which I can't change)which store something like this:
echo $var1
name=fred
age=25
address="123 abc"
password=pass1234
how can I make the variable $name, $age, $address and $password contain the info?
I mean do this in a... (1 Reply)
Discussion started by: freddy1228
1 Replies
5. Shell Programming and Scripting
Dear all,
I have basic knowledge of Unix script and her I am trying to process variable length and variable format CSV file.
The file length will depend on the numbers of Earnings/Deductions/Direct Deposits.
And
The format will depend on whether it is Earnings/Deductions or Direct Deposits... (2 Replies)
Discussion started by: chechun
2 Replies
6. Shell Programming and Scripting
Hi,
I am trying to do the following thing
var='date'
$var
Above command substitutes date for and in turn runs the date command and i am getting the todays date value.
I am trying to do the same thing as following, but facing some problems,
unique_host_pro="sed -e ' /#/d'... (3 Replies)
Discussion started by: gvinayagam
3 Replies
7. Shell Programming and Scripting
can anyone please help me with this:
i have written a shell script and a stored procedure which has one OUT parameter. now i want to use that out parameter as an input to the unix script but i am getting an error as variable not found. below are the unix scripts and stored procedure...
... (4 Replies)
Discussion started by: swap21783
4 Replies
8. Red Hat
Hi all,
Hereby wish to have your advise for below:
Main concept is
I intend to get current directory of my script file.
This script file will be copied to /etc/init.d.
A string in this copy will be replaced with current directory value.
Below is original script file:
... (6 Replies)
Discussion started by: cielle
6 Replies
9. Shell Programming and Scripting
Hi All,
I have a file which has hundred of records with fixed number of fields. In each record there is set of 8 characters which represent the duration of that activity. I want to sum up the duration present in all the records for a report. The problem is the duration changes per record so I... (5 Replies)
Discussion started by: danish0909
5 Replies
10. UNIX for Advanced & Expert Users
I have a below syntax its working fine...
var12=$(ps -ef | grep apache | awk '{print $2,$4}')
Im getting expected output as below:
printf "%b\n" "${VAR12}"
dell 123
dell 456
dell 457
Now I wrote a while loop.. the output of VAR12 should be passed as input parameters to while loop and results... (5 Replies)
Discussion started by: sam@sam
5 Replies
LEARN ABOUT LINUX
filecap
FILECAP:(8) System Administration Utilities FILECAP:(8)
NAME
filecap - a program to see capabilities
SYNOPSIS
filecap [ -a | -d | /dir | /dir/file [cap1 cap2 ...] ]
DESCRIPTION
filecap is a program that prints out a report of programs with file based capabilities. If a file is not in the report or there is no
report at all, no capabilities were found. For expedience, the default is to check only the directories in the PATH environmental variable.
If the -a command line option is given, then all directories will be checked. If a directory is passed, it will recursively check that
directory. If a path to a file is given, it will only check that file. If the path to the file includes capabilities, then they are written
to the file.
OPTIONS
-a This tells the program to show all capabilities starting from the / directory. Normally the PATH environmental variable is used to
show you capabilities on files you are likely to execute.
-d This dumps all capabilities for reference.
EXAMPLES
To check file capabilities in $PATH:
filecap
To check file capabilities of whole system:
filecap -a
To check file capabilities recursively in a directory:
filecap /usr
To check file capabilities of a specific program:
filecap /bin/passwd
To list all possible capabilities:
filecap -d
To set a file capability on a specific program:
filecap /bin/ping net_raw net_admin
SEE ALSO
pscap(8), netcap(8), capabilities(7).
AUTHOR
Steve Grubb
Red Hat March 2009 FILECAP:(8)