The posix-umask program
posix-umask changes its file mode creation mask, then executes a program.
Interface
posix-umask [ -S ] [ mask ] [ prog... ]
When called with no argument, posix-umask prints the value of the file mode creation mask of the invoking process, then exits 0.
When called with a mask argument, posix-umask changes its file mode creation mask; then, if prog... is not empty, it execs into it.
posix-umask interprets mask as specified by the POSIX specification for a umask external utility.
Notes
- When execline has been configured with the --enable-pedantic-posix option, the umask command is a symbolic link to it. So scripts calling umask will use posix-umask. When this configuration option has not been given, umask is a symbolic link to execline-umask.
- posix-umask fully conforms to the POSIX specification. When prog... is not empty, the behaviour of a umask utility is not specified by POSIX, so posix-umask extends the spec to be actually useful and usable in an execline program with the same interface as the regular execline umask command.
- Nobody ever executes or needs the external version (i.e. not a shell builtin) of the POSIX umask command. Compared to execline's regular umask binary, execline-umask, posix-umask is uselessly bloated and slow. The only reason it exists is that some distributions refuse to package execline correctly unless it is strictly POSIX-compliant; the --enable-pedantic-posix configure option is there to satisfy their requirements.