The problem is like this:
There is a script called run, I need to change the operation of run to make the 2nd field of the output of run to be 0 (Please note: it's not the output of run but a part of it). I just don't know how to judge the value of the the 2nd field of the output of run for a loop.
Does anyone have any good ideas? Thank you.
See this snippet :
out=$(command | awk '{print $2}')
((out)) || echo "zero detected"
or simply:
command | awk '($2 == 0) {print "zero detected"}'
On in a for loop :
command | while read a b c d; do
((b)) || echo "zero detected"
done
note:
((...)) is an arithmetic command, which returns an exit status of 0 if the expression is nonzero, or 1 if the expression is zero. Also used as a synonym for "let", if side effects (assignments) are needed. See http://mywiki.wooledge.org/ArithmeticExpression
Capture the output of run in an array and modify the second element like this:
res=($(echo 1 2 3 4))
# show whole array
echo ${res[@]}
1 2 3 4
# show element 2 with index 1:
echo ${res[1]}
2
# modify second element:
res[1]=0
# verify modified element:
echo ${res[1]}
0
# verify whole thing:
echo ${res[@]}
1 0 3 4
so for your command:
res=($(run))
res[1]=0
# usage of manipulated result:
echo ${res[@]}
