* `pushd <newdir>` and `popd` to add current folder to a stack when moving to a new one and returning:
```
~/Desktop$ pushd /
/$popd
~/Desktop$
```

* append `!` to a command to execute the last command with the same beginning:
```
$!ca
> cat Readme.md
```

* Space at the beginning so the command is not added to the history:
```
$ command_with_private_password
```

* `alias cd..='cd ..'` to avoid typos