Shell-具有命令和增量命令值的循环数组

Question

    var1=$(echo $getDate | awk '{print $1} {print $2}')
    var2=$(echo $getDate | awk '{print $3} {print $4}')
    var3=$(echo $getDate | awk '{print $5} {print $6}')

Instead of repeating like the code above, I need to:

1. loop the same command
2. increment the values ({print $1} {print $2})
3. store the value in an array

I was doing something like below but I am stuck maybe someone can help me please:

COMMAND=`find $locationA -type f | wc -l`
getDate=$(find $locationA -type f | xargs ls -lrt | awk '{print $6} {print $7}')
a=1
b=2
for i in $COMMAND
do
   i=$(echo $getDate | awk '{print $a} {print $b}')
   myarray+=('$i')
   a=$((a+1))
   b=$((b+1))
done

PS - using ksh

Problem: $COMMAND stores the number of files found in $locationA. I need to loop through the amount of files found and store their dates in an array.

Answer 1

I don't get the meaning of your example code (what is the 'for' loop supposed to do? What is the content of the variable COMMAND?), but in your question you ask to store something in an array , while in the code you wish to simplify, you don't use an array, but simple variables (var1, var2, ....).

If I understand your requirement correctly, your variable getDate contains a string of several words, which are separated by spaces, and you want to assign the first two words to var1, the following two words to var2, and so on. Is this correct?

Answer 2

Now the edited code is at least a bit clearer, though I still don't understand, why you use i as a loop variable, and overwrite it in the first statement inside the loop.

However, a few comments:

• If you push '$i' into your array, you will get a literal '$' sign, followed by the letter 'i'. To add a variable i containing to numbers, you need double quotes ("$i").

• I don't understand why you want to loop over the cotnent of the variable COMMAND. This variable will always hold a single number, which means that the loop will be executed exactly once.

• You could use a counting loop, incrementing loop variable by 2 on each iteration. You would have to precalculate the number of iterations beforehand.

• Perhaps an easier alternative, which would work in bash or in zsh (I did not try other shells) is to first turn your variable in an array,

  tmparr=($(echo $getDate|fmt -w 1))

and then use a loop to collect pairs of this element:

myarray=()
for ((i=0; i<${#tmparr[*]}; i+=2))
do
    myarray+=("${tmparr[$i]} ${tmparr[$((i+1))]}")
done

${myarray[0]} will hold a string consisting of the first to words from getDate, etc.

Answer 3

This one should work on zsh, at least with newer versions:

myarray=()
echo $g|fmt -w 1|paste -s -d " \n"|while read s; do myarray+=("$s"); done

This leaves the first pair in ${myarray[1]}, etc.

It doesn't work with bash (and old zsh versions), because these shells would execute the body of the loop in a subshell.

ADDED:

On a second thought, in zsh this one would be simpler:

myarray=("${(f)$(echo $g|fmt -w 1|paste -s -d ' \n')}")