Bash capturing output of awk into array

Question

I am stuck on a little problem. I have a command which pipes output to awk but I want to capture the output of to an array one by one.

My example:

myarr=$(ps -u kdride | awk '{ print $1 }')

But that capture all my output into one giant string separated by commas:

output: PID 3856 5339 6483 10448 15313 15314 15315 15316 22348 29589 29593 32657 1

I also tried the following:

IFS=","
myarr=$(ps -u kdride | awk '{ print $1"," }')

But the output is: PID, 3856, 5339, 6483, 10448, 15293, 15294, 15295, 15296, 22348, 29589, 29593, 32657,
1

I want to be able to capture each individual pid into its own array element. Setting IFS = '\n' does not do anything and retains my original output. What change do I need to do to make this work?

You can skip the awk command altogether by using myarr=( $(ps -u kdride -o pid) ). (Note the extra parenthesis as pointed out in Paul's answer). — chepner
– chepner, Commented Feb 27, 2013 at 13:56

Jonathan Leffler · Accepted Answer · 2013-02-27 06:11:47Z

114

Add additional parentheses, like this:

myarr=($(ps -u kdride | awk '{ print $1 }'))

# Now access elements of an array (change "1" to whatever you want)
echo ${myarr[1]}

# Or loop through every element in the array
for i in "${myarr[@]}"
do
   :
  echo $i
done

7 Comments

Paul Over a year ago

Ah much thanks. I skipped over that part entirely. Reference helps much thanks

mmlac Over a year ago

What is the point of the : after the do? Why do we need a true here? I ran it without it and it still worked?

Æzor Æhai -him- Over a year ago

I am also curious why there is a :

Millemila Over a year ago

I am also curious why there is a : please let us know

DeadlyChambers Over a year ago

Has anyone came to verdict on why there is a random colon?

|

jarno · Accepted Answer · 2019-08-14 17:55:12Z

7

Use Bash's builtin mapfile (or its synonym readarray)

mapfile -t -s 1 myarr < <(ps -u myusername | awk '{print $1}')

At least in GNU/Linux you can format output of ps, so no need for awk and -s 1

mapfile -t myarr < <(ps -u myusername -o pid=)

answered Aug 14, 2019 at 17:55

jarno

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3 Comments

baggiponte Over a year ago

why do you need to use < twice?

jarno Over a year ago

@baggiponte It is because I am redirecting process substitution

ClimateUnboxed Nov 29, 2024 at 7:39

not available on the MAC OSX version of bash unfortunately though...

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