When the shell finds met a character in the command line what does it do?

Answer 1

The shell interpreter must substitute or convert all metacharacters in the command line before the command parameters are given to a program. Once all metacharacters have been removed and replaced by their equivalents the program is then executed.

Answer 2

When a meta character is encountered the shell has to substitute the meaning of the metacharacter before anything is executed. For example,

echo hello user $USER

The $ character indicates that the following is a shell variable, and the value of the Shel variable is substituted in the line before the echo command sees the parameter list. So what the echo command utimately might see is:

echo hello user John

Answer 3

There are several meta characters; each one does something different.

Answer 4

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