mjhjmtu

The command below will give me a list of users not with a 1 day min password life. This works correctly.

awk -F: '$4 < 1 print $1' /etc/shadow

I want to take this list, and run...

chage -m 1 $p

where $p is the username on each line.

Normally, i would save this list as a file, and then run a while loop against it. See below for my full command to change all users to 1 day min password.

mkdir ./tmp
awk -F: '$4 < 1 print $1' /etc/shadow > ./tmp/usernamelist

while read p; do
 chage -m 1 $p
done <./tmp/usernamelist

rm -rf ./tmp/usernamelist

Is there a way to do the same thing logically, but without having to save a file? Is this best practice?

I would think there would be a way to do this with a pipe command, but i can't find a proper way to structure it.

Either with a pipe

awk -F: '$4 < 1 print $1' /etc/shadow |
while read p; do
 chage -m 1 "$p"
done

or with process substitution

while read p; do
 chage -m 1 "$p"
done < <(awk -F: '$4 < 1 print $1' /etc/shadow)

awk -F: '$4 < 1 print $1' /etc/shadow | xargs -r -L 1 chage -m 1

The -L 1 ensures that each line of the awk output is passed to a separated chage invocation, and the -r ensures that chage is not run executed if awk doesn't output anything (which, admittedly, is quite unlikely in this case).