Specifications

62 Version 2.0
UEFI_Shell_Command [options] | UEFI_Shell_Command
When piping from an environment variable, the environment variable must already
exist. If it does not, an error will be generated. Any Unicode Byte Ordering Characters
are ignored.
Table 6 Input Redirection Syntax
Character Sequence Description
| Pipe output of a command to another program in UCS-2 format.
|a Pipe output of a command to another program in ASCII format.
When piping to an environment variable, if a new environment variable will be
created, then it will be volatile. If the environment variable already exists and is non-
volatile, an error will be generated.
All output to UCS-2 encoded files will be prefixed with the Unicode Byte Ordering
Character (0xFFFE) if (a) there is at least one other character output and (b) that
character is not the Unicode Byte Ordering Character.
3.5 Current Directory
For each file system, the UEFI Shell maintains a current directory, which is the default
directory used if a directory is not specified in a file path. The UEFI Shell maintains a
current working file system, which is the default file system used if one is not supplied
in a file path. The current directory in the current working file system is the current
working directory.
The current directory for any file system and current working file system can be
retrieved using the GetCurDir() function (see page 34). The current directory for any
file system and the current working file system can be changed using the SetCurDir()
function (see page 57).
The current directory for any file system and current working directory can retrieved
and changed using the cd shell command (see page 95).
The current working directory can be found in the standard %cwd% environment
variable.
3.6 Variables
This section describes the different types of variable substitution that happens on the
command-line for environment variables, positional parameters, index parameters
and aliases.