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| -rw-r--r-- | doc/coreutils.texi | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/doc/coreutils.texi b/doc/coreutils.texi index 7918aec6a..88e16503d 100644 --- a/doc/coreutils.texi +++ b/doc/coreutils.texi @@ -2839,14 +2839,22 @@ tail [@var{option}]@dots{} [@var{file}]@dots{} @end example If more than one @var{file} is specified, @command{tail} prints a -one-line header consisting of: +one-line header before the output for each @var{file}, consisting of: @example ==> @var{file name} <== @end example -@noindent -before the output for each @var{file}. +For further processing of tail output, it can be useful to convert the +file headers to line prefixes, which can be done like: + +@example +tail @dots{} | +awk ' + /^==> .* <==$/ @{prefix=substr($0,5,length-8)":"; next@} + @{print prefix$0@} +' | @dots{} +@end example @cindex BSD @command{tail} GNU @command{tail} can output any amount of data (some other versions of |