I have a unix program lets call it x that processes a file and takes the following parameters:

--fileName: just a text file name
--firstLine: integer
--lastLine: integer
[download]

so a typical invokation could be

x --fileName=foo --firstLine=50 --lastLine=100
[download]

this will read foo from line 5 to line 100 inclusive and produce do something with them

I want to call x few times with (--firstLine,--lastLine) like this

(1,1000) (1001,2000) ....

so effectively I am processing foo in chunks of 1000 lines

if I do this and foo has millions of lines the processing time will increase as I progress with the chunks because x is scanning foo to reach firstLine.

I cannot change x and want to write a Perl wrapper for x that reads foo from line 1 to the end and send every chunk of 1000 lines to x and this way I avoid scannig foo multiple times.

Is this possible?

update (broquaint): added formatting

---

---

• Are you posting in the right place? Check out Where do I post X? to know for sure.
• Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:

  <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>

• Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
• Want more info? How to link or How to display code and escape characters are good places to start.