String to be used to put the output of a filter command in a temporary file. See also |:!|. See |option-backslash| about including spaces and backslashes. The name of the temporary file can be represented by "%s" if necessary (the file name is appended automatically if no %s appears in the value of this option). The default is ">". For Unix, if the 'shell' option is "csh" or "tcsh" during initializations, the default becomes ">&". If the 'shell' option is "sh", "ksh", "mksh", "pdksh", "zsh", "zsh-beta", "bash", "fish", or "pwsh", the default becomes ">%s 2>&1". This means that stderr is also included. For Win32, the Unix checks are done and additionally "cmd" is checked for, which makes the default ">%s 2>&1", and "powershell" is checked for which makes the default "2>&1 | Out-File -Encoding default" (see |dos-powershell|). Also, the same names with ".exe" appended are checked for. The initialization of this option is done after reading the ".vimrc" and the other initializations, so that when the 'shell' option is set there, the 'shellredir' option changes automatically unless it was explicitly set before. In the future pipes may be used for filtering and this option will become obsolete (at least for Unix). This option cannot be set from a |modeline| or in the |sandbox|, for security reasons.