root/galaxy-central/tools/filters/randomlines.xml

<tool id="random_lines1" name="Select random lines">
  <description>from a file</description>
  <command interpreter="python">randomlines.py $input $num_lines $out_file1</command>
  <inputs>
    <param name="num_lines" size="5" type="integer" value="1" label="Randomly select" help="lines"/>
    <param format="txt" name="input" type="data" label="from"/>
  </inputs>
  <outputs>
    <data format="input" name="out_file1" metadata_source="input"/>
  </outputs>
  <tests>
    <test>
      <param name="num_lines" value="65"/>
      <param name="input" value="1.bed"/>
      <output name="out_file1" file="1.bed"/>
    </test>
  </tests>
  <help>

**What it does**

This tool selects N random lines from a file, with no repeats, and preserving ordering.

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**Example**

Input File::

    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  +

Selecting 2 random lines might return this::

    chr7  56736  56756   D17003_CTCF_R7  354  +
    chr7  56775  56795   D17003_CTCF_R4  207  +

    </help>
</tool>