在bash for循环中指定多个条件

Question

So I want to pass a for loop in my bash script, and I want it to stop depending on two parameters:

for (( x=1; x<= 50 -a $array_position -lt ${#array[@]}; x++ ))
do
    echo ${array[$array_position]}
    array_position=$((array_position+1))
done

My intention is to have this for loop echo 50 consecutive array values [0] -- [50], but stop if $array_position reaches the end of the array before all 50 loop iterations complete.

Any help is appreciated, as always!

Answer 1

The problem is the -a or -lt in your for statement. Change it to this:

for (( x=1; x<= 50 && $array_position < ${#array[@]}; x++ ))

Or to simplify the whole thing further:

for (( x=0;  x < 50 && x < ${#array[@]}; x++ ))
do
    echo "${array[$x]}"
done

Answer 2

You should only need to specify the array size as your test, and use a break statement if you reach 50:

for (( x=1; x<=${#array[@]}; x++ ))
do
    echo ${array[$array_position]}
    array_position=$((array_position+1))
    [ $x -eq 50 ] && break
done