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Full Discussion: Help with looping question
Homework and Emergencies Homework & Coursework Questions Help with looping question Post 302519398 by agama on Wednesday 4th of May 2011 12:04:37 AM
Old 05-04-2011
Glad you figured it out on your own!!

Two comments:
First, your user might appreciate knowing which file(s) don't exist by specifically naming it/them in your message. In the case of three inputs that's not too big of a task for the user to track down, but for a real-world programme, with hundreds or thousands of files to check, I would think it would be advantageous to have a list of specifically what doesn't exist.

Secondly, you might also want to look into using the not (!) operator with your logic:
Code:
if [ -e "$i" ]
 then
 echo > /dev/null
 else
 echo ONE OR MORE FILES DO NOT EXSIST!
 exit
 fi

as it would help you to eliminate the echo > /dev/null. Psuedo code:
Code:
   if ! exists $f
   then
      echo "file $f does not exist"
   end

 

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echo(1B)					     SunOS/BSD Compatibility Package Commands						  echo(1B)

NAME
echo - echo arguments to standard output SYNOPSIS
/usr/ucb/echo [-n] [argument] DESCRIPTION
echo writes its arguments, separated by BLANKs and terminated by a NEWLINE, to the standard output. echo is useful for producing diagnostics in command files and for sending known data into a pipe, and for displaying the contents of envi- ronment variables. For example, you can use echo to determine how many subdirectories below the root directory (/) is your current directory, as follows: o echo your current-working-directory's full pathname o pipe the output through tr to translate the path's embedded slash-characters into space-characters o pipe that output through wc -w for a count of the names in your path. example% /usr/bin/echo "echo $PWD | tr '/' ' ' | wc -w" See tr(1) and wc(1) for their functionality. The shells csh(1), ksh(1), and sh(1), each have an echo built-in command, which, by default, will have precedence, and will be invoked if the user calls echo without a full pathname. /usr/ucb/echo and csh's echo() have an -n option, but do not understand back-slashed escape characters. sh's echo(), ksh's echo(), and /usr/bin/echo, on the other hand, understand the black-slashed escape characters, and ksh's echo() also understands a as the audible bell character; however, these commands do not have an -n option. OPTIONS
-n Do not add the NEWLINE to the output. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWscpu | +-----------------------------+-----------------------------+ SEE ALSO
csh(1), echo(1), ksh(1), sh(1), tr(1), wc(1), attributes(5) NOTES
The -n option is a transition aid for BSD applications, and may not be supported in future releases. SunOS 5.10 3 Aug 1994 echo(1B)
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