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Diffstat (limited to 'Doc/Zsh/redirect.yo')
| -rw-r--r-- | Doc/Zsh/redirect.yo | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/Doc/Zsh/redirect.yo b/Doc/Zsh/redirect.yo index b44b07e63..3f30b75a1 100644 --- a/Doc/Zsh/redirect.yo +++ b/Doc/Zsh/redirect.yo @@ -173,11 +173,23 @@ example(echo foo > bar > baz) when tt(MULTIOS) is unset will truncate bar, and write `tt(foo)' into baz. +sect(Redirections with no command) +vindex(NULLCMD, use of) +vindex(READNULLCMD, use of) If a simple command consists of one or more redirection operators -and zero or more parameter assignments, but no command name, -the command named in the shell variable tt(READNULLCMD) is assumed. -(If tt(READNULLCMD) is empty or not set, `tt(cat)' is used.) Thus +and zero or more parameter assignments, but no command name, and the +parameter tt(NULLCMD) is not set, an error is caused. If the parameter +tt(NULLCMD) is set, its value will be inserted as a command with the +given redirections. If both tt(NULLCMD) and tt(READNULLCMD) are set, then +the value of the latter will be used instead of that of the former when the +redirection is an input. The default for tt(NULLCMD) is `tt(cat)' and for +tt(READNULLCMD) is `tt(more)'. Thus example(< file) -copies the contents of tt(file) to the standard output. +shows the contents of tt(file) on standard output, with paging if that is a +terminal. tt(NULLCMD) and tt(READNULLCMD) may refer to shell functions. + +The standard Bourne shell behaviour is obtained by setting tt(NULLCMD) and +tt(READNULLCMD) to `tt(:)'. This is the default when zsh is emulating bf(sh) +or bf(ksh). |