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| author | Peter Stephenson <pws@users.sourceforge.net> | 2005-09-23 17:03:16 +0000 |
|---|---|---|
| committer | Peter Stephenson <pws@users.sourceforge.net> | 2005-09-23 17:03:16 +0000 |
| commit | ad2bd42c858aa7236e7b7404806d16b5b0efb6ac (patch) | |
| tree | 3c7fd50ab1014769c6d59d15145aefca37ed02be /Doc/Zsh/expn.yo | |
| parent | ced5aab522df2754c2fa4581c3538c2cb6d4c1e1 (diff) | |
| download | zsh-ad2bd42c858aa7236e7b7404806d16b5b0efb6ac.tar.gz zsh-ad2bd42c858aa7236e7b7404806d16b5b0efb6ac.tar.xz zsh-ad2bd42c858aa7236e7b7404806d16b5b0efb6ac.zip | |
21758: optimise =(<<<...) to run within the shell.
Diffstat (limited to 'Doc/Zsh/expn.yo')
| -rw-r--r-- | Doc/Zsh/expn.yo | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/Doc/Zsh/expn.yo b/Doc/Zsh/expn.yo index a75513b25..60c74cab1 100644 --- a/Doc/Zsh/expn.yo +++ b/Doc/Zsh/expn.yo @@ -340,6 +340,15 @@ process. This may be used instead of the tt(<) form for a program that expects to lseek (see manref(lseek)(2)) on the input file. +There is an optimisation for substitutions of the form +tt(=LPAR()<<<)var(arg)tt(RPAR()), where var(arg) is a single-word argument +to the here-string redirection tt(<<<). This form produces a file name +containing the value of var(arg) after any substitutions have been +performed. This is handled entirely within the current shell. This is +effectively the reverse of the special form tt($LPAR()<)var(arg)tt(RPAR()) +which treats var(arg) as a file name and replaces it with the file's +contents. + The tt(=) form is useful as both the tt(/dev/fd) and the named pipe implementation of tt(<LPAR())var(...)tt(RPAR()) have drawbacks. In the former case, some programmes may automatically close the file |