A question about grep string

thomas2004ch · 04-22-2013, 06:55 AM

Hi,

In my script I use the 'hostname' to get the hostname of the machine. But I have to check if the got name contains what I am looking for.

Assumed the 'hostname' returns s001ap12.mycompany.com and I want to greo the 's001ap12', how can I do this?

I did as follow but failed:

Code:

...
hostname|grep "s001ap12$" > /dev/null
if [[ $? -eq 0 ]]; then
  echo "this is S001ap12"
  RC=0
fi

Sometimes the hostname could be 'S001IS12', i.e. the grep should be not-case-sensitive.

david1941 · 04-22-2013, 07:16 AM

try the -i flag to ignore case

chrism01 · 04-22-2013, 08:17 AM

Why the trailing '$' in the search string?

thomas2004ch · 04-22-2013, 08:29 AM

The problem is solved.

David the H. · 04-23-2013, 09:52 AM

There should be no need to use grep for this purpose. Just use your shell's built-in text string comparsion tests.

To start with, you haven't mentioned what scripting environment you're talking about. Some shells provide a built in $HOSTNAME envrionment variable for you already. But if not, capture the hostname command into to one.

Code:

host=$( hostname )

Next, there are several different ways to go about testing the string, but I pesonally recommend a case statement, which is fully portable and usually the most efficient.

Code:

case $host in		           #or $HOSTNAME, if available
    s001ap12.*|S001AP12.*)
        echo "this is S001ap12"
        RC=0
    ;;
esac

Another benefit is that you can add as many entries as you need, if you have to test multiple hosts.

If you're using bash, you can more easily make it case-insensitive by converting the input with the appropriate parameter substitution.

Code:

case ${host,,} in		#or $HOSTNAME, if available
    s001ap12.*)
        echo "this is S001ap12"
        RC=0
    ;;
esac

You can also use bash's [[..]] expanded test brackets, which support both globbing and regular expression matches.

http://mywiki.wooledge.org/BashFAQ/031