Script to Join Letters In An Array

Today's script is a follow up to yesterday's post in which we'll join letters of a word that we previously split up into an array. In a Unix shell script, it's relatively simple to do this using any number of methods. For our purposes today, we're going to make it difficult ;)

In today's Unix shell script, we've again written it in sh, for maximum portability between systems. You'll also note that, because of this, we're, again, going to use some very basic methods to get the results we want. As noted, the Bourne shell doesn't provide a lot of the conveniences we've come to expect from the more advanced shells, which necessitates a bit more scripting on our part.

Take a look at today's script and notice how we deal with arrays. Since the Bourne shell does not provide a facility for creating or using arrays, we (essentially) have to fake them. As Unix shell scripting goes, this can be a confusing way to attack the problem. Although, a more accurate statement would probably be that mastering these sorts of Unix scripting methods, and being able to fall back on them, will put you in a position where you will always be able to write a script to accomplish what's required. Who needs all those fancy high-level shell built-in's anyway ;)

Hopefully, you'll find this interesting and helpful.

Best Wishes,





This work is licensed under a
Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License

#!/bin/sh

########################################
# shjoin - mash arrays into strings
#
# 2008 - Mike Golvach - eggi@comcast.net
#
# Usage - shjoin IFS ${array[@]}
#
# Notes - If IFS is a space, or other 
# shell meta-character, be sure to quote
#
# Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License
#
########################################

argvcount=$#

if [ $argvcount -lt 2 ]
then
 exit 1
fi 

TMPIFS=$1
shift
ARRAY=$@

string=`for x in $ARRAY
do
 if [ $x = "\0" ]
 then
  echo " $TMPIFS\c"
 else
 echo "$x$TMPIFS\c"
 fi
done`
newstring=${string}

echo $newstring

, Mike

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