: (colon) -- expand arguments and do nothing, successfully

The : (colon) command simply yields an exit status of zero (success). It does expand its arguments but does nothing with them. This can be surprisingly useful, for example, when you are evaluating shell expressions for their side effects.

EXAMPLES

: ${VAR:="default value"}

sets VAR to a default value if and only if it is not already set.

DIAGNOSTICS

Since this command always succeeds, the only possible exit status is:

0: Successful completion.

PORTABILITY

POSIX.2. x/OPEN Portability Guide 4.0. All UNIX systems. Windows 2000. Windows XP. Windows Server 2003. Windows Vista. Windows 7. Windows Server 2008. Windows 8. Windows Server 2012.

NOTE

This is a special built-in command of the MKS KornShell.

AVAILABILITY

MKS Toolkit for Power Users
MKS Toolkit for System Administrators
MKS Toolkit for Developers
MKS Toolkit for Interoperability
MKS Toolkit for Professional Developers
MKS Toolkit for Enterprise Developers
MKS Toolkit for Enterprise Developers 64-Bit Edition
MKS Integrity

: (colon)
expand arguments and do nothing, successfully

KornShell Built-in

SYNOPSIS

DESCRIPTION