After I wrote prompt $ sort display doesn't shown anything what the next step?
1 Answer
The sort command expects you to provide input – the data that is to be sorted. Normally it is run either with a file name specified (e.g. sort names.txt) to read from it directly, or as part of a pipeline where it receives input via stdin from another program (e.g. ls | sort).
Since you ran it without any input files, it's currently waiting for data input via stdin (which in this case is the terminal).
The next step is therefore either a) to manually type or paste your data into the terminal, followed by CtrlD to indicate EOF, or b) use CtrlC kill the process and re-run it properly with an input file specified.