Which ls flag will display all files, including hidden ones (. and ..)? -a -A -i -r

The -a flag in the ls command displays all files, including hidden ones (those starting with a dot), as well as special directories . and ...

• -a — shows all files, including hidden and . and ..
• -A — shows all hidden files but excludes . and ..
• -i — displays the index numbers of files
• -r — displays the list in reverse order

Therefore, the correct answer is: -a.