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Full Discussion: Bad substitution issues.. but why?
Top Forums UNIX for Beginners Questions & Answers Bad substitution issues.. but why? Post 302980285 by apmcd47 on Thursday 25th of August 2016 05:48:06 PM
Old 08-25-2016
Regarding this line:

Code:
NUMBER_OF_FILES=$(ls ${PATH_TO_DATASET} |  wc -l) # number of directories in the dataset

If there are newline characters in any of the directories (and heaven forbid that there are!) the output of wc -l will be incorrect. May I suggest instead:

Code:
NUMBER_OF_FILES=$(ls -1b ${PATH_TO_DATASET} |  wc -l) # number of directories in the dataset

or:
Code:
NUMBER_OF_FILES=$(ls -1q ${PATH_TO_DATASET} |  wc -l) # number of directories in the dataset

The -b and -q switches suppress the output of "\n" as a character, replacing it with "?" or "\n" as strings respectively.The "-1" switch is redundant, but in my opinion makes it more readable - more obvious that we are expecting a single column out of ls. Either way, the output of wc -l is now the number of directories regardless of strange characters in their names.

Andrew
 

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LEARN ABOUT DEBIAN

dspam_train

dspam_train(1)							       DSPAM							    dspam_train(1)

NAME

       dspam_train - train a corpus of mail

SYNOPSIS

       dspam_train [username] [--client] [-i index|spam_corpus nonspam_corpus]

DESCRIPTION

       dspam_train  is	used  to  train  and test a corpus of mail (in maildir or MBOX format). This tool will present each message to DSPAM for a
       classification and then retrain only if the message was incorrect. This provides close to real-world training and should be used  to  build
       pretrained  databases.  Upon  execution,  the  tool will automatically determine the ratio of spam:nonspam and train based on that ratio to
       ensure both corpora are trained consecutively. This tool can also be used as a test jig to measure the efficiency and accuracy of a partic-
       ular corpus against DSPAM in a given configuration.

OPTIONS

       --client
	      If specified, DSPAM is used in client-server mode.

       username
	      Specifies the user to train, if omitted the current user name is used.

       -i index
	      Use a index file instead of the usual spam_corpus and nonspam_corpus.

	      index :  Path to the index file having the following format per line:
	      [class] [path to message]

       spam_corpus
	      Specifies  either the pathname to the directory containing the corpus of spam, with each in a separate file (e.g. maildir format) or
	      a path to the mailbox in the traditional Unix MBOX format.

       nonspam_corpus
	      Specifies either the pathname to the directory containing the corpus of nonspam with each message in a separate file or  a  path	to
	      the mailbox in the traditional Unix MBOX format.

EXIT VALUE

       0      Operation was successful.
       other  Operation resulted in an error.

COPYRIGHT

       Copyright (C) 2002-2011 DSPAM Project
       All rights reserved.

       For more information, see http://dspam.sourceforge.net.

SEE ALSO

       dspam(1), dspam_admin(1), dspam_clean(1), dspam_crc(1), dspam_dump(1), dspam_logrotate(1), dspam_merge(1), dspam_stats(1)

DSPAM
								   Apr 17, 2010 						    dspam_train(1)
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