Backticks
Using to exec cmd and return the output as string
$ echo `date`
Fri Jun 7 15:40:11 EEST 2024
The same effect you can achieve by using
$ echo $(date)
Fri Jun 7 15:40:11 EEST 2024
Examples
$ echo `date +%F`
2024-06-07
$ echo some log data > blah-`date +%F`.log
# it creates log files blah-2024-06-07.log
arithmetic
With $((...)) expressions, you can do simple arithmetic on the command line.
$ echo $((4*5+1))
21
$ echo Greetings from the year $((`date +%Y`+1000))
Greetings from the year 3024
xargs
Read from stdin, and apply the result to next cmd, kind of like point free sytle.
$ date +%Y | xargs echo Grettings from the year
Greetings from the year 2024