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Filenames can contain any character except only NUL ($'\0') and slash(/); therefore, paths can contain any character except NUL. Here are some guidelines to handle them: Strings containing variables should always be double-quoted to avoid accidental word splitting. The only exception from this is the [[ "var" =~ regex ]] construct, where the regex string must not be quoted.$'...' can be used to create human readable strings with escape sequences.The complicated file name below is used to test that the code is able to handle several common filename issues. -- in commands is necessary to separate arguments from filenames, sincefilenames can start with --, and would therefore be handled as parameters. To handle parameters properly (like most *nix tools) use GNU getopt or the Bash built-in (but more limited) getopts. GNU find doesn't support the -- separator. This is only a problem if the search path is a relative path which doesn't start with ./ (since absolute paths by definition start with a slash, they are not a problem). If the application should support any filename, such paths have to be either converted into absolute paths by using readlink or by adding ./ to the start Variables inside $() have to be quoted just like outside this construct. No additional quoting or escaping is necessary. read usually strips characters in $IFS from the start and end of theresulting variable. Therefore $IFS must be emptied when reading a line. read's -r argument avoids interpreting backslash in filenames specially.read's -d '' argument splits the input by the null character.The $() and `` constructs remove trailing newlines . Getting the original string printed by the commands inside it is a simple matter of adding a single printable character after the last command and then remove it on the next line without using another $(). basename adds a newline to its output, so it has to be stripped in additionto the trailing character. printf %q is a way to print a string so that the result can be copied andpasted into a script, giving the same meaning as the original input string. This can be very useful to see what a variable really contains, including special characters like backspace. Using process substitution with <( instead of pipes avoids a broken pipe in case a process inside the loop exits. find's -exec printf '%s\0' argument separates the output by null characters.Use a file descriptor between 3 and 9 for data passing instead of standard input to avoid greedy commands like cat or ssh slurping all of it.
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