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Top Forums Shell Programming and Scripting Removing Lines if value exist in first file Post 302348776 by Scrutinizer on Saturday 29th of August 2009 04:22:03 PM
Old 08-29-2009
Quote:
Originally Posted by Azhrei
No way would I use a shell for that job! The following Perl script is probably a hundred times faster and more efficient!
While I agree that Perl is usually well suited for this type of application, I do not think this generalization is accurate. The shell scripts above are fine but there is room for some significant speed optimizations. If we use ksh (ksh93s+) instead of bash and a method that resembles the one in your Perl script, I think there would not be a real big difference in speed.

filter.ksh93
Code:
#!/usr/bin/ksh
typeset -A EXCLUDED
EXCLUDE_LIST=$(< $1)
INFILE=$2
for excl in $EXCLUDE_LIST; do
  EXCLUDED[$excl]=1
done
IFS=","
while read a b c id d; do
  if [[ ${EXCLUDED[$id]} -ne 1 ]]; then
    echo "${a},${b},${c},${id},${d}"
  fi
done < $INFILE

Code:
./filter.ksh93 excludes infile > outfile


Last edited by Scrutinizer; 08-29-2009 at 05:32 PM..
 

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let(1)								   User Commands							    let(1)

NAME
let - shell built-in function to evaluate one or more arithmetic expressions SYNOPSIS
ksh let arg... ksh93 let [expr...] DESCRIPTION
ksh Each arg is a separate arithmetic expression to be evaluated. ksh93 let evaluates each expr in the current shell environment as an arithmetic expression using ANSI C syntax. Variables names are shell vari- ables and they are recursively evaluated as arithmetic expressions to get numerical values. let has been made obsolete by the ((...)) syn- tax of ksh93(1) which does not require quoting of the operators to pass them as command arguments. EXIT STATUS
ksh ksh returns the following exit values: 0 The value of the last expression is non-zero. 1 The value of the last expression is zero. ksh93 ksh93 returns the following exit values: 0 The last expr evaluates to a non-zero value. >0 The last expr evaluates to 0 or an error occurred. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWcsu | +-----------------------------+-----------------------------+ SEE ALSO
ksh(1), ksh93(1), set(1), typeset(1), attributes(5) SunOS 5.11 2 Nov 2007 let(1)
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