Why does bash convert .* to hidden file list in current dir and how to prevent it from doing it?

Question

# list=(`echo ".*"`)
# for item in ${list[@]}; do echo "$item"; done;
.
..
.DS_Store
.git
.gitignore
.tox
.toxrc

In the code above, I tried to write a string with .* into an array in bash, but after doing that, the ".*" will be converted to a full file/dir list in current dir. How can I stop bash from doing that?

Answer 1

list=(`echo ".*"`)

In the above, you have no quotes around the command substitution, so the resulting output is subject to word splitting and globbing.

for item in ${list[@]}; do echo "$item"; done;

Also, here, you have no quotes around ${list[@]}, so again, it's subject to word splitting and globbing. (This will matter if you add quotes to the assignment, or if any matching filenames contain whitespace or glob characters...)

If you just want the literal string .*, use list=(".*") and for item in "${list[@]}"; .... If you want to use the command substitution, put quotes around it, i.e. "$(somecmd)".

See also:

• What's the right way to quote $(command $arg)?
• Why does my shell script choke on whitespace or other special characters?
• When is double-quoting necessary?
• WordSplitting on wiki.wooledge.org

Answer 2

The echo … part in the backticks yields the (unquoted) string .*, which is subsequently expanded by BASH. If you don't want the ".*" to be expanded to a list of files, just use list=(".*"). However, I fail to see what the subsequent iteration over such an array would be good for.

Answer 3

From man bash, under options for set :

-f      Disable pathname expansion.

So issue

set -f

to disable globbing, and then

set +f

to re-enable normal globbing behavior.

---

Slightly longer relevant excerpt from the man page:

Pathname Expansion

After word splitting, unless the -f option has been set, bash scans each word for the characters *, ?, and [. If one of these characters appears, then the word is regarded as a pattern, and replaced with an alphabetically sorted list of file names matching the pattern.