how to delete a line from file using awk filtered by some string
- by embedded
I have a file delimited by space.
I need to write an awk command that receives a host name argument
and it should replace the host name if it already defined in the file.
It must be a full match not partially - if the file contains this host name: localhost
searching for "ho" will fail and it will be added to the end of the file.
another option is a delete: again awk receives host name argument and it should remove it from the file if exists.
This is what I have so far: (It needs some enhancements)
if [ "$DELETE_FLAG" == "" ]; then
# In this case the entry should be added or updated
# if clause deals with updating an existing entry
# END clause deals with adding a new entry
awk -F"[ ]" "BEGIN { found = 0;} \
{ \
if ($2 == $HOST_NAME) { \
print \"$IP_ADDRESS $HOST_NAME\"; \
found = 1; \
} else { \
print \$0; \
} \
} \
END { \
if (found == 0) { \
print \"$IP_ADDRESS $HOST_NAME\";
} \
} " \
/etc/hosts > /etc/temp_hosts
else
# Delete an existing entry
awk -F'[ ]' '{if($2 != $HOST_NAME) { print $0} }' /etc/hosts > /etc/temp_hosts
fi
Thanks
