Welcome to Galaxy
It appears that you found this tool from a link outside of Galaxy. If you're not familiar with Galaxy, please consider visiting the welcome page. To learn more about what Galaxy is and what it can do for you, please visit the Galaxy wiki.

Select first (Galaxy tool version 1.0.0)
lines

What it does

This tool outputs specified number of lines from the beginning of a dataset

Example

Selecting 2 lines from this:

chr7  56632  56652  D17003_CTCF_R6  310  +
chr7  56736  56756  D17003_CTCF_R7  354  +
chr7  56761  56781  D17003_CTCF_R4  220  +
chr7  56772  56792  D17003_CTCF_R7  372  +
chr7  56775  56795  D17003_CTCF_R4  207  +

will produce:

chr7  56632  56652  D17003_CTCF_R6  310  +
chr7  56736  56756  D17003_CTCF_R7  354  +