POSIX array and loop

Question

I make an array of files as follows, and then "source" those files. I am also trying to make a script as close to POSIX possible so I don't have issues running it in different shells.

set -- path alias function
for file in "${@}"; do
    [ -r "${SELF_PATH_DIR}.${file}" ] && [ -f "${SELF_PATH_DIR}.${file}" ] && . "${SELF_PATH_DIR}.${file}";
done

It works, but I don't like the fact that I have to specify ${SELF_PATH_DIR}. many times, so that the string takes the real path to the files (/Users/karlsd/dotfiles/.path, etc.).

Is there any way to make it simpler? For example, to add /Users/karlsd/dotfiles/. to each item before the loop?

Socowi · Accepted Answer · 2021-03-14 18:12:52Z

3

Just assign "${SELF_PATH_DIR}.${file}" to a temporary variable or modify the same variable.

By the way: If the loop is the only spot where you are using set --/$@ then you can iterate directly over the list:

for file in path alias function; do
    file="${SELF_PATH_DIR}.${file}"
    [ -r "$file" ] && [ -f "$file" ] && . "$file";
done

answered Mar 14, 2021 at 18:12

Socowi

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Comments

user1934428 · Accepted Answer · 2021-03-15 13:12:12Z

You actually have a potentially larger problem than a mere repetition of the variables: If one of the entries in $@ happens to be the absolute path to some file, your code would break.

I would use realpath inside the loop:

absfile=$(realpath "$file")
[ -r "$absfile" ] && [ -f "$absfile" ] && . "$absfile"

Of course this would silently skip "buggy" entries of file, for instance if the name denotes a directory instead of a plain file or those you have no read access. Unless this is the desired behaviour, I would omit the tests and just source the file. If things aren't right, you get at least an explicit error message.

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