[2.1.1 ls](2.1.1ls.md) [2.1.2 cd](2.1.2cd.md) [2.1.3 pwd](2.1.3pwd.md) [2.1.4 mkdir](2.1.4mkdir.md) [2.1.5 touch](2.1.5touch.md) [2.1.6 mv](2.1.6mv.md) [2.1.7 cp](2.1.7cp.md) [2.1.8 rm](2.1.8rm.md) [2.1.9 file](2.1.9file.md) [2.1.10 cat](2.1.10cat.md) [2.1.11 tree](2.1.11tree.md) [2.1.12 find](2.1.12find.md) [2.1.13 clear](2.1.13clear.md) [2.1.14 chmod](2.1.14chmod.md) [2.1.15 sudo](2.1.15sudo.md) [2.1.16 su](2.1.16su.md) [2.1.17 ping](2.1.17ping.md)