Question: Are there any substitutes, alternatives or bash tricks for delaying commands without using `sleep`? For example, performing the below command without actually using sleep:

```
$ sleep 10 && echo "This is a test"

```

Answer: 
Using the bash built-in variable `$SECONDS` and a busy-loop:

```
for((target=$((SECONDS + 10)); SECONDS < target; true)); do :; done

```
If you want to interactively wait for a new line in a file, then 
```
tail -f
```
.

Waiting for a change on a filesystem? Then use e.g. 
```
inotify / inoticoming
```
.

And there are other options, depending on what you mean with "wait".