[erlang-questions] Read and delete file
Tue Dec 15 07:06:57 CET 2009
My requirement is quite simple,
I have a large file which contains numbers and I shall take those numbers process the numbers and delete the processsed numbers. There are was where I can pause this process at certain conditions and resume when user instructs me to do so.
> From: kagato@REDACTED
> Date: Sat, 12 Dec 2009 02:40:37 -0800
> CC: bengt.kleberg@REDACTED; erlang-questions@REDACTED
> To: maruthavanan_s@REDACTED
> Subject: Re: [erlang-questions] Read and delete file
> Under Unix, there is no good way to delete a line from the front of a file. You can truncate the file (shorten it, cutting lines off at the end), but not from the front.
> If you're willing to do it all on disk (possibly with multiple copies of the data), it can be done, but it's hard to make a recommendation without knowing exactly what you're doing.
> On Dec 12, 2009, at 2:18 AM, maruthavanan s wrote:
> > Hi,
> > The file is huge so I cannot take and keep it in memory.
> > Regards,
> > Marutha
> >> To:
> >> From: bengt.kleberg@REDACTED
> >> CC: erlang-questions@REDACTED
> >> Date: Fri, 11 Dec 2009 15:44:52 +0100
> >> Subject: Re: [erlang-questions] Read and delete file
> >> Greetings,
> >> The simplest way, if you can have the whole file in memory, would be to
> >> read all lines, handle a single line and then write all the remaining
> >> lines out to the file. Then repeat.
> >> Use file:read_file/1 (split the line from the binary) and
> >> file:write_file/2.
> >> bengt
> >> On Fri, 2009-12-11 at 08:50 -0500, maruthavanan s wrote:
> >>> Hi,
> >>> I am opening a file using file and I read the file line by line using io:get_line.
> >>> But after reading this line I need to delete the read line from the file.
> >>> Appreciate you help.
> >>> Thanks,
> >>> Marutha
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