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Full Discussion: using 'more' instead of 'cat' to pipe into another command
Top Forums UNIX for Dummies Questions & Answers using 'more' instead of 'cat' to pipe into another command Post 302434199 by css136 on Thursday 1st of July 2010 08:00:58 PM
Old 07-01-2010
using 'more' instead of 'cat' to pipe into another command
Hi, quick question. Since i am in the habit of using 'more' to view files, e.g.

Code:
$ more my_file.txt

I often use this command to pipe into other utilities like grep. For example,

Code:
$ more my_file.txt | grep '^>'

would get all lines in the file that begin with ">". I know that it is generally recommended to use 'cat' for this purpose, so I was wondering if there is a speed difference between the two commands? In other words, would it be faster to say:

Code:
$ cat my_file.txt | grep '^>'

? Since i routinely work with very large text files, the speed difference could be important.



(Note: I realize that 'grep' takes a file argument like this:
Code:
$ grep '^>' my_file.txt

but i am only using it as an example. It can be anything. I am more interested in the 'cat' vs. 'more' difference.)

Thanks!
Last edited by pludi; 07-01-2010 at 10:48 PM.. Reason: code tags, please...
 

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LEARN ABOUT POSIX

zgrep

ZGREP(1)						      General Commands Manual							  ZGREP(1)

NAME

       zgrep - search possibly compressed files for a regular expression

SYNOPSIS

       zgrep [ grep_options ] [ -e ] pattern filename...

DESCRIPTION

       Zgrep  invokes  grep  on  compressed  or  gzipped  files.   These  grep	options  will  cause  zgrep  to  terminate  with  an  error  code:
       (-[drRzZ]|--di*|--exc*|--inc*|--rec*|--nu*).  All other options specified are passed directly to grep.  If no file is specified,  then  the
       standard input is decompressed if necessary and fed to grep.  Otherwise the given files are uncompressed if necessary and fed to grep.

       If the GREP environment variable is set, zgrep uses it as the grep program to be invoked.

EXIT CODE

       2 - An option that is not supported was specified.

AUTHOR

       Charles Levert (charles@comm.polymtl.ca)

SEE ALSO

       grep(1), gzexe(1), gzip(1), zdiff(1), zforce(1), zmore(1), znew(1)

																	  ZGREP(1)
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