UNIX for Dummies Questions & Answers

I have a file with the following text:

Code:

grep \$
grep \\$
grep \\\$
grep '\$'
grep '\'$'
grep \\
grep \\\\
grep "\$"
grep '"$'
grep "$"

When I perform these same commands on this file, the result are never what I would expect them to be. Could someone please comment on the results and help me clarify this?

Thank you.

Some confused me too. Very interesting questions.

For that it would be interesting to know which shell you are using, and what results you would expect.

I'm using Bourne shell (not bash). Well, not one of my expectations was realized. All others were wrong.

Code:

grep \$

Me: all lines with $ in them
Unix: all lines

Code:

grep \\$

Me: well, the first \ escapes the second \, so it's just a plain \. $ would need to be followed by an environmental variable, I suppose, but since it isn't, it's just plain $.
Unix: all lines with $ in them

Code:

grep \\\$

Me: all lines with \$ (literally) in them
Unix: all line with $ in them.

Code:

grep '\$'

Me: all lines with \$ (literally) in them
Unix: all lines with $ in them

Code:

grep '\'$'

Me: first it would show a secondary prompt, so I could finish the string. Then it would search for \$ (literally).
Unix: first it showed a secondary prompt, after finishing the string with an ', it said "error 41: No remembered search string."

Code:

grep \\

Me: all lines with \ in them
Unix: "error 50: Regular expression overflow."

Code:

grep \\\\

Me: a line with \\ (two \'s literally) in it
Unix: all lines with \ in them

Code:

grep "\$"

Me: all lines with $ in them
Unix: all lines

Code:

grep '"$'

Me: all lines with "$ in them
Unix: all lines with $ or $". I'm not sure.

Code:

grep "$"

Me: all lines with $ in them
Unix: all lines.

Maybe when I write $ by itself, the shell expands that into an empty string, therefore the search returns everything?

The others, I'm simply baffled.