Command: if

  IF performs conditional processing in batch programs.
  IF is a BATCH-FILE / AUTOEXEC.BAT command.
  It can also be used in command line.

Syntax:

  IF [NOT] ERRORLEVEL Nummer command
  IF [NOT] string1==string2 command
  IF [NOT] EXIST filename command
     drive     The drive letter, e.g. C:
     path      The directory, e.g. \example\
     filename  The file, e.g. test.txt

Options:

  NOT               Specifies that the command shell should carry out
                    the command only if the condition is false.
                    (Without this, the command will be run if the
                    condition is true.)
  ERRORLEVEL number Specifies a true condition if the last program run
                    returned an exit code equal to or greater than the
                    number specified.
  command           Specifies the command to carry out if the condition
                    is met.
  string1==string2  Specifies a true condition if the specified text
                    strings match.
  EXIST filename    Specifies a true condition if the specified filename
                    exists.

Comments:

  ERRORLEVEL number:   DOS Programs return a number when they exit,
                       which sometimes contains information on
                       whether the program was successful. If the
                       last program to exit returned the given number,
                       then the condition is true.
  string1==string2     If the two strings of characters are equal,
                       then the condition is true.
  exist [drive][path]  If the given file is there, then the condition
        filename       is true.

  IF is a command internal to command.com and needs no other file
  in order to work.

Examples:

  IN A .BAT FILE / AUTOEXEC.BAT:
    if exist c:\kernel.sys ECHO Kernel exists 
                  (gives a message if kernel exists)
    set A=freedos
    set B=freedos
    set C=otherdos
    if %A%==%B% ECHO A and B are same string  
                  (A and B are "freedos", so the message will appear)
    if %A%==%C% ECHO A and C are same string
                  (A is "freedos", C is "otherdos", so no message 
                   will appear)
    if not %A%==%C% ECHO A and C are not same string 
                  (A is "freedos", C is "otherdos", as they are NOT 
                   the same, the message will appear)

Command: if

Syntax:

Options:

Comments:

Examples:

See also: