Unable to grep file for due to unknown end line character?

Unable to grep file for due to unknown end line character?

I have a CSV file which is parsed by a bash script in order to find the
position of a given ID within the file, as a means of tracking progress
via JMeter.
The specific line I'm having trouble with consists of this code:
egrep -n -C 2 '49156$'
Previously I've run the script with no problem, however I think something
funny has happened to the character encoding or the end line characters.
As now when I run this line I get no return.
If I change the regex to check for an extra character, such as '49156.$'
then I get the following in OSX and Ubuntu:
OSX: 1307-node/49150 1308-node/49153 1309:node/49156 1310-node/49159
1311-node/49162
Ubuntu: 1307-node/49150 1308-node/49153
1310-node/49159
1311-node/49162
I need the script to run on an Ubuntu server, so I really need to get it
functioning on that, however as I said, the script has run fine with
previous CSVs, I'm really not sure how this most recent CSV has become
altered.
If I look at the file in VIM using :set list I see the following:
node/49153$
node/49156$
node/49159$
node/49162$
node/49165$
I thought to check for numeric block instead of the end line character,
using the pattern: '49156[^0-9]' however this still produces the same
result:
1307-node/49150
1308-node/49153
1310-node/49159
1311-node/49162
Other than the above, I'm not really sure what to test for next. Thanks
for any advice :)