Shell script arrays

Question

I would like to set array elements with loop:

for i in 0 1 2 3 4 5 6 7 8 9
do
array[$i] = 'sg'
done

echo $array[0]
echo $array[1]

So it does not work. How to..?

Answer 1

# Declare Array

NAMEOFSEARCHENGINE=( Google Yahoo Bing Blekko Rediff )

# get length of an array
arrayLength=${#NAMEOFSEARCHENGINE[@]}

# use for loop read all name of search engine
for (( i=0; i<${arrayLength}; i++ ));
do
  echo ${NAMEOFSEARCHENGINE[$i]}
done

Output:

Google
Yahoo
Bing
Blekko
Rediff

Answer 2

My take on that loop:

array=( $(yes sg | head -n10) )

Or even simpler:

array=( sg sg sg sg sg sg sg sg sg sg )

See http://ideone.com/DsQOZ for some proof. Note also, bash 4+ readarray:

readarray array -t -n 10 < <(yes "whole lines in array" | head -n 10)

In fact, readarray is most versatile, e.g. get the top 10 PIDs of processes with bash in the name into array (which could return an array size<10 if there aren't 10 such processes):

readarray array -t -n 10 < <(pgrep -f bash)

Answer 3

there is problem with your echo statement: give ${array[0]} and ${array[1]}

Answer 4

It should work if you had declared your variable as array, and print it properly:

declare -a array
for i in 0 1 2 3 4 5 6 7 8 9 
do
    array[$i]="sg"
done
echo ${array[0]} 
echo ${array[1]} 

See it in action here.

HTH

Answer 5

Remove the spaces:

array[$i]='sg'

Also, you should access the elements as^*:

echo ${array[0]}

See e.g. http://tldp.org/LDP/abs/html/arrays.html.

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_{* Thanks to @Mat for reminding me of this!}