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using regex to get part of a string ?

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# 1  
Old 08-24-2009
using regex to get part of a string ?
Hi there, i wonder, is it possible to use regular expressions to partially select a string?

I have a bunch of server names which look like this


server1z-test
server2z2
server45z-primary
server13z3

I want to extract up to and including the 'z' in the server name, so for example


server1z
server2z
server45z
server13

everything to the right of the 'z' im not interested in

using the example above, is this possible using regular expressions?
# 2  
Old 08-24-2009
Something like this?

Code:
sed 's/\(.*z\).*/\1/'

Or shorter:

Code:
sed 's/z.*/z/'

With shell variable substring:

Code:
echo ${var/z*/z}

# 3  
Old 08-24-2009
Quote:
Originally Posted by Franklin52
Code:
echo ${var/z*/z}


That is non standard. The portable syntax is:

Code:
echo "${var%"${var#*z}"}"

# 4  
Old 08-24-2009
Quote:
Originally Posted by cfajohnson

That is non standard. The portable syntax is:

Code:
echo "${var%"${var#*z}"}"

Ok, thanks for the filling up!
# 5  
Old 08-24-2009
thanks guys, If you get a chance, would you be able to explain to me what exactly is happening with these two commands

echo "${var%"${var#*z}"}"

sed 's/\(.*z\).*/\1/'

the var% is somewhat confusing and with regards to the second snippet, why is the "1" at the end... Thank you for posting those, if theres any way youd be able to explain them that would be great
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