Shell Programming and Scripting

$ trap "echo I\'m out..." exit
$ set -o nounset -o errexit
$ find ./t -name "*.lib"|while read library; do echo $libary; done
bash: libary: unbound variable
$ while read library; do echo $libary; done< <(find ./t -name "*.lib")
bash: libary: unbound variable
I'm out...

% cat s
#!/bin/bash -ue

find ./t -name "*.lib"|while read library;do
  echo $libary
done

echo after the first loop # you'll see it

while read library;do
  echo $libary
done< <(find ./t -name "*.lib")

echo after the second one # you won't see it

ubuntux% ./s
./s: line 4: libary: unbound variable
after the first loop
./s: line 10: libary: unbound variable

set -o nounset
#set -o errexit
find . -name "*.txt" | while read library; do
echo ${libary}
done
RC=$?  #return status of the previous command
if [ $RC -ne 0 ]
then
        exit
fi
echo "after while"

% cat s
#!/bin/bash -ue
find ./t -name "*.lib"|while read correct;do
  echo $wrong
  echo $correct
done||exit

echo after the loop

% ./s
./s: line 3: wrong: unbound variable
% sh s

./t/1.lib
after the loop
% sh -ue s
s: 5: wrong: parameter not set

% cat s
#!/bin/bash -ue

find ./t -name "*.lib"|while read correct;do
  echo $wrong
  echo $correct
done

echo after the loop

% sh s

./t/1.lib
after the loop
% sh -uevx s
#!/bin/bash -ue

find ./t -name "*.lib"|while read correct;do
  echo $wrong
  echo $correct
done
+ find ./t -name *.lib
+ read correct
s: 1: wrong: parameter not set