====== SED - Align - Center all text in the middle of 79-column width ======

<code bash>
sed  -e :a -e 's/^.\{1,77\}$/ & /;ta'                     # method 1
sed  -e :a -e 's/^.\{1,77\}$/ &/;ta' -e 's/\( *\)\1/\1/'  # method 2
</code>

<WRAP info>
**NOTE:**  

  * In method 1, spaces at the beginning of the line are significant, and trailing spaces are appended at the end of the line.
  * In method 2, spaces at the beginning of the line are discarded in centering the line, and no trailing spaces appear at the end of lines.

</WRAP>