new to Ubuntu was wondering if anyone can explain why one only shows the user and username and the other shows more information? what's the difference between $USER and USER


In the first form,

env | grep $USER

The variable $USER is expanded to its value for grep. So, grep will show all lines which contains the value of $USER variable. For me, the value of $USER is anwar. So the command is equivalent to env | grep anwar

If you want to grep the literal $USER, use single quote as suggested in this answer

In the second form,

env | grep USER

only the literal USER is used for grepping and thus grep will only show those lines containing USER.

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