how to find and replace only the 2nd occurrence of similar string in a file

hchoonbeng · 10-08-2008, 03:42 AM

hi how do u replace only the 2nd occurence of similar string in a file?
eg in test.txt

num_oper = 1
oper = mem

i wrote a script to replace only oper the 2nd object in test.txt but it seem that both num_oper and oper got replaced. my script is as follow:

sed -n s/oper=[a-z]*/oper=rim/p test.txt

output:

num_oper = rim1
oper = rim

Mr. C. · 10-08-2008, 03:44 AM

In this case, use

sed -n s/^oper=[a-z]*/oper=rim/p