Linux shell command

Interactive commands: Variable content is determined by the user

Read [-PT] Variable

-P: Can be followed by a prompt

-T: The number of seconds to wait after

echo [-ne] String

echo [--help] [--version]

-N: Do not wrap in the last line

-E: If the following characters are present, they will be treated specially, not as general text output

\a issued a warning sound;
\b Delete the previous character;
\c finally not add the line break symbol;
\f the line but the cursor remains in its original position;
\ n Wraps and the cursor moves to the beginning of the line;
\ r The cursor moves to the beginning of the line, but does not wrap;
\ t Insert tab;
\v is the same as \f;
\ \ insert \ character;
\NNN inserts the ASCII character represented by the NNN (octal);

-help: Display Help

-version: Display version information

Linux shell command