Print a line character by character by showing whitespaces:
$ dmesg | sed -n -e '7p' | od -a
0000000 [ sp sp sp sp sp 1 , 0 0 0 0 0 0 ] sp
0000020 N e t B S D sp 9 . 0 sp ( X E N 3
0000040 _ D O M U ) sp # 0 : sp F r i sp F
0000060 e b sp 1 4 sp 0 0 : 0 6 : 2 8 sp U
0000100 T C sp 2 0 2 0 nl
0000110Match the lines with inconsistent indentations in a set of Python files:
$ find . -name "*.py" -print -exec grep -n -P "^\t" '{}' \;
./foo.py
./bar.py
42: """This is a comment