How to get word x from a string

Question

I want to read a file line by line as following:

while read line;
do
  set -- $line
  c=$#  #count words and save as $c
  r=$(( RANDOM%c ))
  #here i'd like to get the word on position r from $line
done < words.txt

I know, I can get word 1 as following:

set -- $line
echo $1

But how can I replace 1 with the integer saved in $r?

Related: [Dynamic variable names in Bash](https://stackoverflow.com/q/16553089/4518341) — wjandrea, Jun 27 '19 at 14:46

score 1 · Accepted Answer · answered Jun 27 '19 at 14:48

1

Use indirection:

echo "${!r}"

For example:

$ set -- a b c
$ echo $2
b
$ v=2
$ echo ${!v}
b

answered Jun 27 '19 at 14:48

wjandrea

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On second thought, don't do this. Use an array instead. See [my other answer](https://stackoverflow.com/a/56793714/4518341) – wjandrea Jun 27 '19 at 14:52

score 1 · Answer 2 · answered Jun 27 '19 at 14:52

1

Use an array instead:

words=($line)
echo "${words[$r]}"

For example:

$ var words
declare -a words='([0]="a" [1]="b" [2]="c")'
$ v=2
$ echo "${words[v]}"
c
$ echo "${words[v-1]}"
b

answered Jun 27 '19 at 14:52

wjandrea

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81

How to get word x from a string

2 Answers2