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Full Discussion: Delete first 100 lines from a BIG File
Top Forums UNIX for Advanced & Expert Users Delete first 100 lines from a BIG File Post 302657443 by Scrutinizer on Sunday 17th of June 2012 06:02:59 PM
Old 06-17-2012
It seems to me any solution should always make use a temporary intermediate file for safety reasons. If we read the whole file into memory and then write it back to the same file, we run the risk of losing the original in case of power failure during the write-back phase..

With a temporary file there is only mv involved, which is only a rename if the temporary file is in the same dir on the same file system, so a temporary file in the same directory instead of /tmp for example may be preferably. If we use /tmp for example for the intermediate file, a temporary rename to .bak of the original until the move from /tmp may be required and safest will probably be to keep the .bak until the user deletes it..
 

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LEARN ABOUT OSX

zipnote

zipnote(1)						      General Commands Manual							zipnote(1)

NAME

       zipnote - write the comments in zipfile to stdout, edit comments and rename files in zipfile

SYNOPSIS

       zipnote [-w] [-b path] [-h] [-v] [-L] zipfile

ARGUMENTS

       zipfile	Zipfile to read comments from or edit.

OPTIONS

       -w     Write comments to a zipfile from stdin (see below).

       -b path
	      Use path for the temporary zip file.

       -h     Show a short help.

       -v     Show version information.

       -L     Show software license.

DESCRIPTION

       zipnote	writes the comments in a zipfile to stdout.  This is the default mode.	A second mode allows updating the comments in a zipfile as
       well as allows changing the names of the files in the zipfile.  These modes are described below.

EXAMPLES

       To write all comments in a zipfile to stdout use for example

	    zipnote foo.zip > foo.tmp

       This writes all comments in the zipfile foo.zip to the file foo.tmp in a specific format.

       If desired, this file can then be edited to change the comments and then used to update the zipfile.

	    zipnote -w foo.zip < foo.tmp

       The names of the files in the zipfile can also be changed in this way.  This is done by following lines like
	    "@ name"
       in the created temporary file (called foo.tmp here) with lines like
	    "@=newname"
       and then using the -w option as above.

BUGS

       The temporary file format is rather specific and zipnote is rather picky about it.  It should be easier to change file names in a script.

       Does not yet support large (> 2 GB) or split archives.

SEE ALSO

       zip(1), unzip(1)

AUTHOR

       Info-ZIP

								v3.0 of 8 May 2008							zipnote(1)
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