Shell Programming and Scripting

Hello, I am trying to run a shell script with the nohup command. The shell script takes an array of files, runs a python program on each file in a loop, and appends the output to a file. This works fine on the server, but if I try to use the nohup command it does not work.

---

Code:

#!/bin/sh
ARRAY=(0010.dat 0020.dat 0030.dat)

rm batch_results.dat
touch batch0.dat
touch batch_results.dat

for file in ${ARRAY[@]}
do
python fof.py $file > /dev/null
python mdisk5.py > ./batch0.dat
tail -1 batch0.dat
tail -1 batch0.dat >> batch_results.dat
done

---

The program works fine when I run it while staying connected to the server, for example

Code:

./batch.sh > /dev/null &
./batch.sh > ./output.txt &

However, when I try to run it with the nohup command,

Code:

nohup ./batch.sh > /dev/null &

if I exit the server and come back the output file (batch_results.dat) does not have any data.

I am sure I am missing some simple fix or command in here. Any ideas?

What does the nohup.out file show?

It does not exist. Generally I redirect to ./output.txt, which is blank, or /dev/null

What happens when you do this:

Code:

nohup ./batch.sh &

or this.

Code:

nohup ./batch.sh >/dev/null 2>&1 </dev/null &

these also did not work:

Code:

nohup ./batch.sh &
nohup ./batch.sh >/dev/null </dev/null &

this gave 'Ambiguous output redirect.':

Code:

nohup ./batch.sh >/dev/null 2>&1 </dev/null &

Are you running csh or tcsh? If so, try running from /bin/sh.

I am running csh. I tried nohup /bin/sh batch.sh & and some other variations and it also did not work.

I have used nohup successfully on these servers working with other programs. I routinely use nohup ./Main.out > /dev/null & and will run programs for days.

I am not sure if my shell script isn't working because I am piping the output of multiple python runs to different things or what.