11-13-2011
output redirection to existing file question
So I have a existing file that I used the uniq command on and I need to save the output to the same file without changing the file name.
I have tried $ uniq filename > filename
then when I cat the file it then becomes blank like there is nothing inside.
any help would be much appreciated thanks.
Last edited by pludi; 11-13-2011 at 02:35 PM..
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UNIQ(1) FSF UNIQ(1)
NAME
uniq - remove duplicate lines from a sorted file
SYNOPSIS
uniq [OPTION]... [INPUT [OUTPUT]]
DESCRIPTION
Discard all but one of successive identical lines from INPUT (or standard input), writing to OUTPUT (or standard output).
Mandatory arguments to long options are mandatory for short options too.
-c, --count
prefix lines by the number of occurrences
-d, --repeated
only print duplicate lines
-D, --all-repeated[=delimit-method] print all duplicate lines
delimit-method={none(default),prepend,separate} Delimiting is done with blank lines.
-f, --skip-fields=N
avoid comparing the first N fields
-i, --ignore-case
ignore differences in case when comparing
-s, --skip-chars=N
avoid comparing the first N characters
-u, --unique
only print unique lines
-w, --check-chars=N
compare no more than N characters in lines
--help display this help and exit
--version
output version information and exit
A field is a run of whitespace, then non-whitespace characters. Fields are skipped before chars.
AUTHOR
Written by Richard Stallman and David MacKenzie.
REPORTING BUGS
Report bugs to <bug-coreutils@gnu.org>.
COPYRIGHT
Copyright (C) 2002 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICU-
LAR PURPOSE.
SEE ALSO
The full documentation for uniq is maintained as a Texinfo manual. If the info and uniq programs are properly installed at your site, the
command
info uniq
should give you access to the complete manual.
uniq (coreutils) 4.5.3 February 2003 UNIQ(1)