Return to Answer

When you copy using cp -a source/* target/ you are copying most of the files and directories from source to target. Specifically, the items that are excluded will probably be files beginning with a dot (.) in the top level of source.

Consider these files (or directories) in source

apple        # will be copied
banana/      # will be copied, as will all its contents
.cherry      # will not be copied

When you copy using cp -a source/. target/ you are copying the entire contents of source, including any items beginning with a dot (.) to target

Consider these files (or directories) in source

apple        # will be copied
banana/      # will be copied, as will all its contents
.cherry      # will be copied

If you're using bash, zsh, you can use the dotglob option to change the meaning of * so that it includes files and directories beginning with a dot (yash also has a dotglob option; however, it then includes . and .. in glob expansions which limits its usability. See also FIGNORE='@(.|..)' in ksh93).

Interestingly, cp -a source/. target/ is guaranteed never to create the component target/source. (On the other hand, cp -a source target/ will do one of two things depending on whether or not target already exists. See How to copy a folder recursively in an idempotent way using cp for the details.)

When you delete using rm -rf source/* you are deleting the files and directories within source that do not begin with a dot (.). Subject to the dotglob setting I've already mentioned. It will not delete the directory source itself.

When you try to delete using rm -rf source/. it will fail - as others have already explained - becuase POSIX prohibits deletion of a path whose last component is . or ... The closest equivalent is rm -rf source, which will delete the source directory and all its contents regardless of whether or not they begin with a dot (.).

When you copy using cp -a source/* target/ you are copying most of the files and directories from source to target. Specifically, the items that are excluded will probably be files beginning with a dot (.) in the top level of source.

Consider these files (or directories) in source

apple        # will be copied
banana/      # will be copied, as will all its contents
.cherry      # will not be copied

When you copy using cp -a source/. target/ you are copying the entire contents of source, including any items beginning with a dot (.) to target

Consider these files (or directories) in source

apple        # will be copied
banana/      # will be copied, as will all its contents
.cherry      # will be copied

If you're using bash, zsh, you can use the dotglob option to change the meaning of * so that it includes files and directories beginning with a dot (yash also has a dotglob option; however, it then includes . and .. in glob expansions which limits its usability. See also FIGNORE='@(.|..)' in ksh93).

Interestingly, cp -a source/. target/ is guaranteed never to create the component target/source. (On the other hand, cp -a source target/ will do one of two things depending on whether or not target already exists. See How to copy a folder recursively in an idempotent way using cp for the details.)

When you delete using rm -rf source/* you are deleting the files and directories within source that do not begin with a dot (.). Subject to the dotglob setting I've already mentioned. It will not delete the directory source itself.

When you try to delete using rm -rf source/. it will fail - as others have already explained - because POSIX prohibits deletion of a path whose last component is . or ... The closest equivalent is rm -rf source, which will delete the source directory and all its contents regardless of whether or not they begin with a dot (.).

When you copy using cp -a source/* target/ you are copying most of the files and directories from source to target. Specifically, the items that are excluded will probably be files beginning with a dot (.) in the top level of source.

Consider these files (or directories) in source

apple        # will be copied
banana/      # will be copied, as will all its contents
.cherry      # will not be copied

When you copy using cp -a source/. target/ you are copying the entire contents of source, including any items beginning with a dot (.) to target

Consider these files (or directories) in source

apple        # will be copied
banana/      # will be copied, as will all its contents
.cherry      # will be copied

If you're using bash you can use the dotglob option to change the meaning of * so that it includes files and directories beginning with a dot.

Interestingly, cp -a source/. target/ is guaranteed never to create the component target/source. (On the other hand, cp -a source target/ will do one of two things depending on whether or not target already exists. See How to copy a folder recursively in an idempotent way using cp for the details.)

When you delete using rm -rf source/* you are deleting the files and directories within source that do not begin with a dot (.). Subject to the dotglob setting I've already mentioned. It will not delete the directory source itself.

When you try to delete using rm -rf source/. it will fail - as others have already explained - becuase POSIX prohibits deletion of a path whose last component is . or ... The closest equivalent is rm -rf source, which will delete the source directory and all its contents regardless of whether or not they begin with a dot (.).

When you copy using cp -a source/* target/ you are copying most of the files and directories from source to target. Specifically, the items that are excluded will probably be files beginning with a dot (.) in the top level of source.

Consider these files (or directories) in source

apple        # will be copied
banana/      # will be copied, as will all its contents
.cherry      # will not be copied

When you copy using cp -a source/. target/ you are copying the entire contents of source, including any items beginning with a dot (.) to target

Consider these files (or directories) in source

apple        # will be copied
banana/      # will be copied, as will all its contents
.cherry      # will be copied

If you're using bash, zsh, you can use the dotglob option to change the meaning of * so that it includes files and directories beginning with a dot (yash also has a dotglob option; however, it then includes . and .. in glob expansions which limits its usability. See also FIGNORE='@(.|..)' in ksh93).

Interestingly, cp -a source/. target/ is guaranteed never to create the component target/source. (On the other hand, cp -a source target/ will do one of two things depending on whether or not target already exists. See How to copy a folder recursively in an idempotent way using cp for the details.)

When you delete using rm -rf source/* you are deleting the files and directories within source that do not begin with a dot (.). Subject to the dotglob setting I've already mentioned. It will not delete the directory source itself.

When you try to delete using rm -rf source/. it will fail - as others have already explained - becuase POSIX prohibits deletion of a path whose last component is . or ... The closest equivalent is rm -rf source, which will delete the source directory and all its contents regardless of whether or not they begin with a dot (.).

When you copy using cp -a source/* target/ you are copying most of the files and directories from source to target. Specifically, the items that are excluded will probably be files beginning with a dot (.) in the top level of source.

Consider these files (or directories) in source

apple        # will be copied
banana/      # will be copied, as will all its contents
.cherry      # will not be copied

When you copy using cp -a source/. target/ you are copying the entire contents of source, including any items beginning with a dot (.) to target

Consider these files (or directories) in source

apple        # will be copied
banana/      # will be copied, as will all its contents
.cherry      # will be copied

If you're using bash you can use the dotglob option to change the meaning of * so that it includes files and directories beginning with a dot.

When you copy using cp -a source/* target/ you are copying most of the files and directories from source to target. Specifically, the items that are excluded will probably be files beginning with a dot (.) in the top level of source.

Consider these files (or directories) in source

apple        # will be copied
banana/      # will be copied, as will all its contents
.cherry      # will not be copied

When you copy using cp -a source/. target/ you are copying the entire contents of source, including any items beginning with a dot (.) to target

Consider these files (or directories) in source

apple        # will be copied
banana/      # will be copied, as will all its contents
.cherry      # will be copied

If you're using bash you can use the dotglob option to change the meaning of * so that it includes files and directories beginning with a dot.

Interestingly, cp -a source/. target/ is guaranteed never to create the component target/source. (On the other hand, cp -a source target/ will do one of two things depending on whether or not target already exists. See How to copy a folder recursively in an idempotent way using cp for the details.)

When you delete using rm -rf source/* you are deleting the files and directories within source that do not begin with a dot (.). Subject to the dotglob setting I've already mentioned. It will not delete the directory source itself.

When you try to delete using rm -rf source/. it will fail - as others have already explained - becuase POSIX prohibits deletion of a path whose last component is . or ... The closest equivalent is rm -rf source, which will delete the source directory and all its contents regardless of whether or not they begin with a dot (.).