Specific syntax for the make command line

Last revision August 4, 2004

Table of contents: Managing programming source code with make How does make work? Specific syntax for lines in the makefile Specific syntax for the make command line

Typing
      make
as a Unix shell command causes the following actions:

• make reads the script in the file named makefile in the current directory, if it exists; otherwise it reads the file named Makefile, if it exists. If neither exists, it quits with an error.
• After processing macro definitions, target dependencies and commands in the makefile, make chooses the first target in the file as its objective and recreates the generators and the target as necessary. If that target is already fully up to date, make just prints a message.

Two of the things that you would like to be able to do are to specify a different filename for the makefile and to specify a target other than the first in the file.

Use the -f option followed by a filename to specify a different filename for the makefile, for example:
     make -f makefile.test

To specify a target or targets to process, other than the default first target, just give the target names (no colons) on the command line after make. Examples:
     make prog1 prog2
     make clean

You can also specify macro definitions on the command line to override those in the makefile. Use the syntax
      macroname=string_of_characters
right on the command line, but enclose the whole thing in quotes so the shell does not try to process metacharacters or split at embedded blanks.

Example:
     make 'LIBS= -lvplot -lloc'
would override the specification
      LIBS = -lloc
that was already in a makefile.

There are other options described in the make documentation. One useful one is -n which shows which commands make would execute, but does not actually execute them. This allows you to preview what make would do.