string-join0 - join strings with zero bytes¶

Synopsis¶

string join [-q | --quiet] SEP [STRING ...]
string join0 [-q | --quiet] [STRING ...]

Description¶

string join joins its STRING arguments into a single string separated by SEP, which can be an empty string. Exit status: 0 if at least one join was performed, or 1 otherwise. If -n or --no-empty is specified, empty strings are excluded from consideration (e.g. string join -n + a b "" c would expand to a+b+c not a+b++c).

string join0 joins its STRING arguments into a single string separated by the zero byte (NUL), and adds a trailing NUL. This is most useful in conjunction with tools that accept NUL-delimited input, such as sort -z. Exit status: 0 if at least one join was performed, or 1 otherwise.

Because Unix uses NUL as the string terminator, passing the output of string join0 as an argument to a command (via a command substitution) won’t actually work. Fish will pass the correct bytes along, but the command won’t be able to tell where the argument ends. This is a limitation of Unix’ argument passing.

Examples¶

>_ seq 3 | string join ...
1...2...3

# Give a list of NUL-separated filenames to du (this is a GNU extension)
>_ string join0 file1 file2 file\nwith\nmultiple\nlines | du --files0-from=-

# Just put the strings together without a separator
>_ string join '' a b c
abc