Change existing variable value only user enters non-empty string.


 
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# 8  
Old 05-20-2010
Kchinnam, you are seeing the newlines ('\n") in your od output because you are using the echo command to pipe the variable in question to od. The echo command adds a newline to its output by design.

Try the following example
Code:
uid="scott"
echo "${uid}" |  od -bcx
printf "${uid}" |  od -bcx

gid=
echo "${gid}" |  od -bcx
printf "${gid}" |  od -bcx

Here is the output from this example
Code:
$ ./example
0000000  163 143 157 164 164 012
           s   c   o   t   t  \n
            6373    746f    0a74
0000006
0000000  163 143 157 164 164
           s   c   o   t   t
            6373    746f    0074
0000005
0000000  012
          \n
            000a
0000001
$

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RABBITMQ-ENV.CONF(5)						  RabbitMQ Server					      RABBITMQ-ENV.CONF(5)

NAME
rabbitmq-env.conf - default settings for RabbitMQ AMQP server DESCRIPTION
/etc/rabbitmq/rabbitmq-env.conf contains variable settings that override the defaults built in to the RabbitMQ startup scripts. The file is interpreted by the system shell, and so should consist of a sequence of shell environment variable definitions. Normal shell syntax is permitted (since the file is sourced using the shell "." operator), including line comments starting with "#". In order of preference, the startup scripts get their values from the environment, from /etc/rabbitmq/rabbitmq-env.conf and finally from the built-in default values. For example, for the RABBITMQ_NODENAME setting, RABBITMQ_NODENAME from the environment is checked first. If it is absent or equal to the empty string, then NODENAME from /etc/rabbitmq/rabbitmq-env.conf is checked. If it is also absent or set equal to the empty string then the default value from the startup script is used. The variable names in /etc/rabbitmq/rabbitmq-env.conf are always equal to the environment variable names, with the RABBITMQ_ prefix removed: RABBITMQ_NODE_PORT from the environment becomes NODE_PORT in the /etc/rabbitmq/rabbitmq-env.conf file, etc. # I am a complete /etc/rabbitmq/rabbitmq-env.conf file. # Comment lines start with a hash character. # This is a /bin/sh script file - use ordinary envt var syntax NODENAME=hare SEE ALSO
rabbitmq-server(1) rabbitmqctl(1) EXAMPLES
# I am a complete /etc/rabbitmq/rabbitmq-env.conf file. # Comment lines start with a hash character. # This is a /bin/sh script file - use ordinary envt var syntax NODENAME=hare This is an example of a complete /etc/rabbitmq/rabbitmq-env.conf file that overrides the default Erlang node name from "rabbit" to "hare". AUTHOR
The RabbitMQ Team <info@rabbitmq.com> RabbitMQ Server 06/22/2012 RABBITMQ-ENV.CONF(5)