Set the value of a variable with the result of a command in a Windows batch file

Question

When working in a Bash environment  to set the value of a variable as the result of a command  I usually do   var   command -args    where var is the variable set by the command command -args  I can then access that variable as  var   A more conventional way to do this which is compatible with almost every Unix shell is   set var  command -args    That said  how can I set the value of a variable with the result of a command in a Windows batch file  I ve tried   set var command -args   But I find that var is set to command -args rather than the output of the command

User · Answer

Here are two approaches   echo off                                                                      set  quot     gt  quot   quot  2 gt  amp 1 amp set p  quot  amp set  quot      lt    amp  del  q    gt nul 2 gt  amp 1 quot   amp                                                                          --examples    assigning chcp command output to  code-page  variable chcp     code-page     echo 1   code-page     assigning whoami command output to  its-me  variable whoami     its-me     echo 2   its-me                                                         set  quot    for  f  quot tokens   delims  quot      in    quot   amp      set  quot --    do  set  quot  quot                          amp      set  quot         quot  quot                                 amp                                                           --examples    assigning ver output to  win-ver  variable      ver  -- win-ver     echo 3   win-ver      assigning hostname output to  my-host  variable      hostname  -- my-host     echo 4   my-host

User · Answer

The only way I ve seen it done is if you do this   for  f  delims    a in   ver   do  set foobar  a   ver is the version command for Windows and on my system it produces   Microsoft Windows  Version 6 0 6001    Source

User · Answer

One needs to be somewhat careful  since the Windows batch command   for  f  delims     a in   command   do  set theValue   a   does not have the same semantics as the Unix shell statement   theValue  command    Consider the case where the command fails  causing an error   In the Unix shell version  the assignment to  theValue  still occurs  any previous value being replaced with an empty value   In the Windows batch version  it s the  for  command which handles the error  and the  do  clause is never reached -- so any previous value of  theValue  will be retained   To get more Unix-like semantics in Windows batch script  you must ensure that assignment takes place   set theValue  for  f  delims     a in   command   do  set theValue   a   Failing to clear the variable s value when converting a Unix script to Windows batch can be a cause of subtle errors

User · Answer

Here s how I do it when I need a database query s results in my batch file   sqlplus -S schema schema db  query sql gt    query tmp set  p result  lt   query tmp del   query tmp   The key is in line 2   set  p  sets the value of  result  to the value of the first line  only  in    query tmp  via the   lt   redirection operator

User · Answer

Set  dateTime   For  F   A In   powershell get-date -format   yyyyMMdd HHmm     Do Set  dateTime   A  echo  dateTime  pause    Official Microsoft docs for for command

User · Answer

To do what Jesse describes  from a Windows batch file you will need to write   for  f  delims     a in   ver   do  set foobar   a    But  I instead suggest using Cygwin on your Windows system if you are used to Unix-type scripting

[windows] Set the value of a variable with the result of a command in a Windows batch file

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