How to hand over arguments containing "-" in Bash? [duplicate]

Question

This question already has answers here:

Match with grep when pattern contains hyphen "-" (2 answers)

Closed 6 years ago.

I tried to use the grep command to search for a string like -R in a file. But the command thinks, that I am trying to hand over an option like -i for ignore case.

• jsotola: i think that you wrote the answer in your question ... use "-R" , not -R
• user313992: @jsotola are you serious? to the op: use grep -e -R ./-file1 file2, where -R is a pattern starting with -, and ./-file1 is a filename starting with -.
• Freddy: The answer is here: What does "--" (double-dash) mean? (also known as "bare double dash")
• Adrian: Thank you, @Freddy and pizdelect, both of your answers work for me!

Answer 1

The -e option for grep is for explicitly saying "the next argument is the pattern":

grep -e -R file

The above would search for line matching -R in the file called file.

The -e option may occur multiple times on the command line, and grep will use all the given patterns (you will get the lines back that matches any of the patterns).

Answer 2

As well as the previously mentioned answers, -- is used to signify the end of options, allowing you to use patterns afterward that may resemble an argument without being interpreted undesirably:

$ echo -R | grep -- '-R'
-R

Answer 3

Try to escape the characters grep \\-R myfile.txt:

Example:

$ touch test.txt
$ echo "-R" >> ./test.txt
$ cat test.txt
-R
$ grep \\-R ./test.txt
-R

• Adrian: Thank you, your answer also works for me!