!makes this line special because
#is used as comment line in bash.
VARIABLE="value". We can do the same thing in a script, as an example:
), or with a pair of backticks, we can substitute the command’s output as input to another command. This technique is called command substitution.
./scriptnameif we are in the same directory
$PATHdirectories or editting
testcommand which is writter as
test EXPRESSIONit is the same as
[ EXPRESSION ].
readcommand read a line from the standard input.
forloop processes each item in a sequence
$before the variable name, although you can if you want.
exec lsand compare results.
mailutilsinstalled. Then we can send mail:
-soption to add a subject line,
<redirection function to redirect it as input to the
catto combine them and pipe the output to