NAME

apply − apply a command to a set of arguments

SYNOPSIS

apply [ −v ] [ −Pn ] [ −ac ] [ −n ] command args ... 

DESCRIPTION

Apply runs the named command on each argument arg in turn.  Normally arguments are chosen singly; the optional number n specifies the number of arguments to be passed to command.  If n is zero, command is run without arguments once for each arg.  Character sequences of the form %d in command, where d is a digit from 1 to 9, are replaced by the d’th following unused arg.  If any such sequences occur, n is ignored, and the number of arguments passed to command is the maximum value of d in command.  The character ‘%’ may be changed by the −a option.  The −v option causes apply to print each command to stderr before it is run. 

Examples:

apply echo ∗

is similar to ls(1);

apply −2 cmp a1 b1 a2 b2 ... 

compares the ‘a’ files to the ‘b’ files;

apply −0 who 1 2 3 4 5

runs who(1) 5 times; and

apply ´ln %1 /usr/joe´ ∗

links all files in the current directory to the directory /usr/joe. 

PARALLEL SUPPORT

Apply runs n commands concurrently, where n is given in the -Pn option.  If the -Pn option is missing, apply looks for the environment variable PARALLEL and uses its numeric value for n.  If this fails, n defaults to 1. 

SEE ALSO

sh(1), make(1), environ(7)

AUTHOR

Rob Pike

BUGS

Shell metacharacters in command may have bizarre effects; it is best to enclose complicated commands in single quotes ´ ´.  There is no way to pass a literal ‘%2’ if ‘%’ is the argument expansion character.

7th Edition