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deepblue_86
Asked: 2019-01-08 02:41:44 +0800 CST

Duplicate rows in text file

  • 772

I need to duplicate rows in text file with a specific number of times. For example my data file is:

jplg3350.18i
jplg3360.18i
jplg3370.18i

I need to duplicate the lines three times as follows;

jplg3350.18i
jplg3360.18i
jplg3370.18i
jplg3350.18i
jplg3360.18i
jplg3370.18i
jplg3350.18i
jplg3360.18i
jplg3370.18i
bash text-processing

1 Answers

  1. Best Answer

    For 3 times you can just run:

    cat file file file > new_file

    And here is a trick if you're lazy like me and you don't want to re-type the file name N times. Type cat then the filename, Press Ctrl+W, then Ctrl+YSpace N times, finally type > new_file.

    However it's a better idea to use a simple "loop" in combination with cat command.

    • 3 times example:

      for i in {1..3}; do cat file >> new_file; done

    Or as you asked in comments:

    limit=3
for ((i=0; i<limit; i++)); do cat file >> new_file; done

    Change '3' to any number you want.

    Result:

    jplg3350.18i
jplg3360.18i
jplg3370.18i
jplg3350.18i
jplg3360.18i
jplg3370.18i
jplg3350.18i
jplg3360.18i
jplg3370.18i
    • 10