commandline session
$ 4.2.36 4 501---> which $ 4.2.36 5 502---> which -h Illegal option -h Usage: /usr/bin/which [-a] args $ 4.2.36 6 503---> which ls /bin/ls $ 4.2.36 7 504---> which -a ls /bin/ls $ 4.2.36 8 505---> which -a top /usr/bin/top $ 4.2.36 9 506---> which top /usr/bin/top $ 4.2.36 10 507---> echo $? 0 $ 4.2.36 11 508---> which to $ 4.2.36 12 509---> echo $? 1 $ 4.2.36 13 510---> which -k top Illegal option -k Usage: /usr/bin/which [-a] args $ 4.2.36 14 511---> echo $? 2 $ 4.2.36 15 512--->