How to grep for the dollar symbol ($)?

Question

% cat temp
$$$ hello1
$$  hello2
    hello3
##  hello4
    hello5 $$$
% cat temp | grep \"$$$\"
Illegal variable name.
% cat temp | grep \"\\$\\$\\$\"
Variable name          


        

Answer 1

Same issue with this command

complete -W "\`grep -oE '^[a-zA-Z0-9_.-]+:([^=]|$)' Makefile \`"

Illegal variable name.

Answer 2

How about ^.*[$]{3}.*$

Answer 3

The problem is that the shell expands variable names inside double-quoted strings. So for "$$$" it tries to read a variable name starting with the first $.

In single quotes, on the other hand, variables are not expanded. Therefore, '$$$' would work – if it were not for the fact that $ is a special character in regular expressions denoting the line ending. So it needs to be escaped: '\$\$\$'.

Answer 4

Works for me:

user@host:~$ cat temp | grep '\$\$\$'
$$$ hello1
hello5 $$$
user@host:~$ 

Answer 5

$ grep '\$\$\$' temp
$$$ hello1
hello5 $$$

There's a superflous 'cat' in your command.

Answer 6

When you use double quotes " or none use double\: "\\\$\\\$\\\$"

cat t | grep \\\$\\\$\\\$ 

if you use in single quotes ' you may use:

cat t | grep '\$\$\$'