which command (obtains the paths of external commands)

Format

which[-a]command-name ...

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Description

This command obtains the paths of external commands to be executed from the command search path set in the PATH environment variable. The command outputs the obtained command paths to the standard output.

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Arguments

-a

Specifies that all executable command paths are to be obtained from the command search path set in the PATH environment variable.

When the -a option is omitted, the command output only the first command path obtained.

command-name

Specifies the name of an external command whose command path is to be obtained. You can specify multiple command names.

If the command path of a specified external command is not found, the which command outputs a message to that effect to the standard error output.

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Command path search rules

The command searches for the command paths of external commands according to the rules described below.

In Windows:

Paths subject to external command search

The command searches the command search path set in the PATH environment variable for the external commands. If multiple command paths are set in the PATH environment variable, the command searches the command paths in order from the beginning. If the user executing the which command does not have permissions to read the external command storage directory, that directory is not subject to command path search.

External commands whose command paths are to be output

If the user executing the which command has permissions to read the external command storage directory, the which command outputs the corresponding command paths. The which command does not check whether the user has permissions to execute the external command.

The which command can output the paths of external commands if they are executable files with the extension .com, .exe, .cmd, or .bat.

If a specified external command contains no extension, the which command adds the extensions defined in the PATHEXT environment variable in the order defined and then searches the external commands. The supported extensions are .com, .exe, .cmd, and .bat. For details, see 5.1.11 Specifying external commands.

In UNIX:

Paths subject to external command search

The command searches the command search path set in the PATH environment variable for the external commands. If multiple command paths are set in the PATH environment variable, the command searches the command paths in order from the beginning. If the user executing the which command does not have permissions to search the external command storage directory (including all directories in the path), that directory is not subject to command path search.

External commands whose command paths are to be output

If the user executing the which command has permissions to execute a specified external command, the which command determines that that external command is executable and outputs its command path. If the user does not have permissions to execute a specified external command, that external command's path is not output.

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Return code

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Notes

• If the PATH environment variable is undefined, the command terminates with an error.

• In Windows, if the PATHEXT environment variable is undefined, the command terminates with an error.

• If the following names are specified as command names in the argument, the which command treats them as external commands:

  • Aliases defined by the alias command

  • Reserved words, standard shell commands, extended shell commands, and functions

• If a command name specified in the argument contains a path and the path name is subject to conversion by either of the environment setting parameters listed below, the which command outputs the path name obtained after conversion:

  • PATH_CONV parameter

  • COMMAND_CONV_ARG parameter

• In Windows, only external commands that satisfy the command path search rules are subject to output of command paths.

  In the case of commands that are specified in the system function of the awk command and commands that are executed from the command line specified in the -exec option of the find command, paths are searched as follows:

  • Commands specified in the system function of the awk command:

    The path search rules for command processor execution (such as the command prompt) are used as the path search rules for command execution.

  • Command line specified in the -exec option of the find command:

    The path search rules for the Windows API that executes the program are used as the path search rules for command line execution.

  Note that the command path that is output when a command name specified in the above command is specified in the argument might differ from the path of the command that is executed.

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Usage examples

• Obtain the command path of command pgm01.exe:

  C:\TEMP>%ADSH_OSCMD_DIR%\which pgm01.exe
  C:\Program Files\Hitachi\PP001\pgm01.exe

• Obtain the command path of command pgm01. This example omits the extension of the command name:

  C:\TEMP>%ADSH_OSCMD_DIR%\which pgm01
  C:\Program Files\Hitachi\PP001\pgm01.exe

• Specify the -a option to obtain all command paths of command pgm01.exe:

  C:\TEMP>%ADSH_OSCMD_DIR%\which -a pgm01.exe
  C:\Program Files\Hitachi\PP001\pgm01.exe
  C:\Program Files\Hitachi\PP002\pgm01.exe
  C:\Program Files\Hitachi\PP003\pgm01.exe

• Obtain the command path of command pgm02. In this example, the command search path does not contain pgm02:

  C:\TEMP>%ADSH_OSCMD_DIR%\which pgm02
  which: no pgm02 in (C:\WINDOWS\system32;C:\WINDOWS;C:\Program Files\Hitachi\PP001
  ;C:\Program Files\Hitachi\PP002;C:\Program Files\Hitachi\PP003)

• Obtain the command paths of the commands pgm01,pgm02, pgm03, and pgm04. In this example, the command search path does not contain the commands pgm02 and pgm04:

  C:\TEMP>%ADSH_OSCMD_DIR%\which pgm01 pgm02 pgm03 pgm04
  C:\Program Files\Hitachi\PP001\pgm01.exe
  which: no pgm02 in (C:\WINDOWS\system32;C:\WINDOWS;C:\Program Files\Hitachi\PP001
  ;C:\Program Files\Hitachi\PP002;C:\Program Files\Hitachi\PP003)
  C:\Program Files\Hitachi\PP001\pgm03.exe
  which: no pgm04 in (C:\WINDOWS\system32;C:\WINDOWS;C:\Program Files\Hitachi\PP001
  ;C:\Program Files\Hitachi\PP002;C:\Program Files\Hitachi\PP003)

• Execute the which command with a command name containing a path specified. In this example, the specified program name exists:

  C:\TEMP>%ADSH_OSCMD_DIR%\which "C:\Program Files\Hitachi\PP001\pgm01"
  C:\Program Files\Hitachi\PP001\pgm01.exe

• Execute the which command with a command name containing a path specified. In this example, the specified program name does not exist:

  C:\TEMP>%ADSH_OSCMD_DIR%\which "C:\Program Files\Hitachi\PP001\pgm02"
  which: no pgm02 in (C:\Program Files\Hitachi\PP001)

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