Shell Programming and Scripting

Hi Folks,

very basic question, how to do command piping for an array?

suppose i have names as an array, when I write this script:

#!/usr/bin/sh
date=`date +%y%m%d`;
names="a b"
for name in ${names[@]}
do extract -tz +8 person 'income$|expense$' /home/ricki/$name/$date*.xml | tab -d -cols ctr -fmt csv | tee /home/ricki/$name_$date.txt
done

extract and tab are existing perl scripts.

seems that the names array is not stored after executing the first command.. sorry if the question is very basic, i'm a newbie in shell.

//ricki

names is not and never was an array. The shell splits it into a list when you give it ${names}, the same way echo is given the arguments a and b seperately when you do echo a b . The shell always does this unless you force it not to by surrounding a string with double quotes, i.e. "${names}". Single quotes, on the other hand, force it to take the string entirely literally and substitute no variables at all.

/bin/sh in fact is not strictly required to support arrays at all, but bash or ksh both do and often stand in for plain sh anyway. If your program demands arrays it ought to use one of those and not sh.

An array and loop in bash:

Code:

#!/bin/bash
NAMES=( a b )
for ((N=0; N<${#NAMES[*]}; N++))
do
  echo "${NAMES[$N]}"
done