bash > set -eu > diffの実行から下の処理が実行されない > diffのexit codeが異なるため | no_exit_diff()関数を用意する

Xeon E5-2620 v4 (8コア) x 2
32GB RAM
CentOS 6.8 (64bit)
NCAR Command Language Version 6.3.0
for WRF3.7.1, WPS3.7.1
  openmpi-1.8.x86_64 とその-devel
  mpich.x86_64 3.1-5.el6とその-devel
  gcc version 4.4.7 (とgfortran)
for WRF3.9, WPS3.9
  Open MPI v2.1.1
  gcc version 4.9.2 (とgfortran; devtoolset-3使用)
　NetCDF v4.4.1.1, NetCDF (Fortran API) v4.4.4
Python 2.6.6 (r266:84292, Aug 18 2016, 15:13:37) 
Python 3.6.0 on virtualenv
GNU bash, version 4.1.2(1)-release (x86_64-redhat-linux-gnu)
date (GNU coreutils) 8.4 
tmux 1.6-3.el6

$ cat dat1.txt 
LON 135.0
LAT 35.0
$ cat dat2.txt 
LON 135.0
LAT 34.0
$ cat new_lon.txt 
LON 136.0
LAT 35.0

#!/usr/bin/env bash
set -eu

diff dat1.txt new_lon.txt > diff_lon

for elem in $(ls)
do
  echo $elem
done

$ bash patch_lon_180228_exec

#!/usr/bin/env bash
#set -eu

diff dat1.txt new_lon.txt > diff_lon

for elem in $(ls)
do
  echo $elem
done

$ bash patch_lon_180228_exec 
dat1.txt
dat2.txt
diff_lon
new_lon.txt
patch_lon_180228_exec