bash - ash 是否具有与 bash 的 'nullglob' 选项等效的选项？

Question

如果 glob 模式不匹配任何文件，bash 将只返回文字模式:

bash-4.1# echo nonexistent-file-*
nonexistent-file-*
bash-4.1#

您可以通过设置 nullglob shell 选项来修改默认行为，这样如果没有匹配项，您将得到一个空字符串:

bash-4.1# shopt -s nullglob
bash-4.1# echo nonexistent-file-*

bash-4.1# 

那么 ash 中是否有等效的选项？

bash-4.1# ash
~ # echo nonexistent-file-*
nonexistent-file-*
~ # shopt -s nullglob
ash: shopt: not found
~ # 

Answer 1

对于没有 nullglob 的 shell，例如 ash 和 dash:

IFS="`printf '\n\t'`"   # Remove 'space', so filenames with spaces work well.

# Correct glob use: always use "for" loop, prefix glob, check for existence:
for file in ./* ; do        # Use "./*", NEVER bare "*"
    if [ -e "$file" ] ; then  # Make sure it isn't an empty match
        COMMAND ... "$file" ...
    fi
done

来源:Filenames and Pathnames in Shell: How to do it correctly ( cached )