bash：標準出力も標準エラーもログに出力 ref: http://qiita.com/okisanjp/items/4bdf009176ecae312f84

file0.txt

#!/bin/sh

echo "foo"
cat ./sonna_file_naiyo.txt
echo "bar"

file1.txt

$ sh ./test.sh | tee test.log
foo
cat: ./sonna_file_naiyo.txt: No such file or directory
bar

file2.txt

$ cat ./test.log 
foo
bar

file3.txt

$ sh ./test.sh 2>&1 | tee test.log
foo
cat: ./sonna_file_naiyo.txt: No such file or directory
bar

file4.txt

$ cat ./test.log 
foo
cat: ./sonna_file_naiyo.txt: No such file or directory
bar

file5.txt

$ sh ./test.sh > test.log 2>&1

$ cat test.log 
foo
cat: ./sonna_file_naiyo.txt: No such file or directory
bar

file6.txt

$ sh ./test.sh | tee test.log 2>&1
foo
cat: ./sonna_file_naiyo.txt: No such file or directory
bar

$ cat test.log 
foo
bar

file7.txt

$ sh ./test.sh 2>&1 > test.log
cat: ./sonna_file_naiyo.txt: No such file or directory

$ cat test.log 
foo
bar