Command substitution
In the keyboard, there is one interesting key, the backward quote such as "`". This key is normally situated below the Esc key. If we place text between two successive back quotes, then echo
will execute those as commands instead of processing them as plane text.
Alternate syntax for $(command)
is the backtick character "`", which we can see as follows:
$(command) or `command`
For example:
- We need to use proper double quoted inverted commas, as follows:
$ echo "Hello, whoami"
- The next command will print the text as it is; such as
Hello, whoami
:Hello, whoami
- Use proper double inverted commas:
$ echo "Hello, `whoami`." Hello, student
When we enclose
whoami
text in the "`" character, the same text which was printed as plain text will run as a command, and the command output will be printed on screen. - Use proper double inverted commas:
$ echo "Hello, $(whoami)." Hello, student.
Same like the earlier explanation.
Another...