Pulling from the same data position from multiple arrays in bash - arrays

Question

BACKGROUND
What I'm trying to do here is read from a file that has PID information and separate the columns out into arrays. I have completed this part already, though I think is a better way than what I currently have (catting the same file 4 times).
pid=( $(cat /tmp/deadpidlist.log | awk -F " " '{print $1}') )
cpu=( $(cat /tmp/deadpidlist.log | awk -F " " '{print $2}') )
mem=( $(cat /tmp/deadpidlist.log | awk -F " " '{print $3}') )
ctime=( $(cat /tmp/deadpidlist.log | awk -F " " '{print $4}') )
WHAT AM I DOING? oh god
After that, I need to loop through each PID and if the pid fits the criteria I am looking for, put the corresponding cpu usage, memory usage and cpu time beside it in a file and then email that file out.
for i in "${pid[#]}"
do
...
if grep -Fxq "$pattern" /tmp/or_report.log; then
echo "$i" >> /tmp/deadpidwalking.log
I have the rest of my code up on a gist here: https://gist.github.com/sithtoast/e1654adab3cceb137ba2
Thanks!

Answer 1

A simple loop in bash should be sufficient. Note the rarely seen use of subscripted arrays as arguments to read.
declare -a pid cpu mem ctime
i=-1
while ((i++)); read "pid[i]" "cpu[i]" "mem[i]" "ctime[i]" and_the_rest; do
:
done < /tmp/deadpidlist.log
A more straightforward loop would be
declare -a pid cpu mem ctime
while read a b c d and_the_rest; do
pid+=("$a")
cpu+=("$b")
mem+=("$c")
ctime+=("$d")
done < /tmp/deadpidlist.log

Answer 2

Use associative arrays for cpu, mem, and ctime. Also, read the input all in one pass via the read builtin.
declare -a pid
declare -A cpu
declare -A mem
declare -A ctime
while read this_pid this_cpu this_mem this_ctime tail; do
pid[${#pid[*]}]=$this_pid
cpu[$this_pid]=$this_cpu
mem[$this_pid]=$this_mem
ctime[$this_pid]=$this_ctime
done < /tmp/deadpidlist.log
for i in "${pid[#]}" do;
# ...
echo $i cpu[$i] mem[$i] ctime[$i]
done

Answer 3

For the 1st part:
while read -r ipid icpu imem ictime icmd
do
pid+=($ipid)
cpu+=($icpu)
mem+=($imem)
ctime+=($ictime)
cmd+=($icmd)
done < /tmp/deadpidlist.log
Some small comments for the gist:
Use functions. You can save much typing redirecting the output from a function - like:
some() {
echo some
cat /some/file
}
#later
some >> /some/outfile
also, you can save many echo with grouping them into one heredoc
some2() {
cat - <<EOF
some output what want
can use $variables
$(date) #command substitutions too
EOF
}
If you don't want variable expansions, use the heredoc as <<'EOF'
Also, you can use
let countertwo++ #instead of countertwo=$((countertwo + 1))