Error: bash: $: command not found

If you see this error, the most probable reason is, you have copy-pasted an example command-line snippet starting with the $ character in it.

Let us see an error sample:
[admin@devopsrun1 source]$ $ ls
-bash: $: command not found
Note: the actual command typed is "ls" and not "$ ls"

Example of correct usage

Now, look at this correct use:
[admin@devopsrun1 source]$ ls
file1.txt  file2.txt  file3.txt  file4.txt  file5.txt  file6.txt  file7.txt  file8.txt  file9.txt