Neo4j is a popular graph database which provides an easy way to import text files using the Cypher query language and a LOAD CSV clause. LOAD CSV by default expects files to be delimited by commas. In order to specify another field delimiter, add FIELDTERMINATOR to the LOAD CSV clause. For example:

USING PERIODIC COMMIT
LOAD CSV WITH HEADERS FROM "file:///twitter_relationships_top_100.txt" AS line
FIELDTERMINATOR '\t'
CREATE (u:User {username: line.username});

The statement above loads the tab separated twitter_relationships_top_100.txt file (with headers) into the database, creating User labels/nodes with a username property for each record. A small sample of this file can be seen below:

username	followers	followed_by
charliesheen	11593973	shaq
charliesheen	11593973	wizkhalifa
charliesheen	11593973	pharrell
charliesheen	11593973	kevinhart4real
charliesheen	11593973	pitbull
charliesheen	11593973	johncena
charliesheen	11593973	ludacris
charliesheen	11593973	niallofficial
charliesheen	11593973	rickygervais

For a more detailed description of the LOAD CSV clause, please refer to the Neo4j documentation at the Neo4j LOAD CSV page.