apply

apply [-a char] [-d] [-#] command argument...

apply runs a command repeatedly, passing a specified number of arguments to each invocation. It provides a simple alternative to xargs or shell loops for applying a command across multiple arguments.By default, apply passes one argument at a time to the command. With -2, it groups arguments in pairs, useful for commands like diff or cmp that take two files. The %n placeholders allow flexible positioning of arguments within the command string.When the command contains spaces or special characters, it should be quoted. Without placeholders, arguments are appended to the end of the command.

-a char

Use char as the placeholder (magic) character instead of the default %.

A numeric flag (e.g. -2) sets how many arguments to pass per invocation. The default is -1 (one argument at a time). With -0 the command runs once per argument with no arguments passed. Ignored if %d sequences appear in the command.

Dry-run: print the commands that would be executed without running them.

In the command string, %1, %2, ... %9 are replaced by the 1st, 2nd, ... following unused argument.

This command is primarily available on BSD systems and macOS; it is not part of GNU coreutils. Linux users typically use xargs or shell loops instead. The argument count must divide evenly into the total arguments when using -n.

The apply command originated in BSD Unix in the 1980s. It provided a simple mechanism for command iteration before more sophisticated tools like xargs and find -exec became common. The command remains available in FreeBSD, OpenBSD, and macOS but was never widely adopted on Linux systems.

xargs(1), parallel(1), find(1)

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