explainshell.com - grep.1posix -lRE %27errorutil%5C.Handler%27 %7C xargs sed -i -E %27s%2FHandler%5C%28%28%5BA-Za-z0-9_%5C.%5D%2B%29%5C%29%2FHandler%28%5C1%2C %22default value%22%29%2F%27

search a file for a pattern

-l     (The letter ell.) Write only the names of files containing  selected  lines  to  standard  output.
       Pathnames  shall  be written once per file searched. If the standard input is searched, a pathname
       of "(standard input)" shall be written, in the POSIX locale. In other  locales,  "standard  input"
       may be replaced by something more appropriate in those locales.

-E     Match using extended regular expressions. Treat each pattern specified as an ERE, as described  in
       the  Base  Definitions  volume of IEEE Std 1003.1-2001, Section 9.4, Extended Regular Expressions.
       If any entire ERE pattern matches some part of an input line excluding the terminating  <newline>,
       the line shall be matched.  A null ERE shall match every line.

-i     Perform  pattern  matching  in searches without regard to case; see the Base Definitions volume of
       IEEE Std 1003.1-2001, Section 9.2, Regular Expression General Requirements.