Shell – Echoing something with multiple quotes and key characters (&, $, !, etc.)

You can use the following string literal syntax:

> echo $'\'single quote phrase\' "double quote phrase"'
'single quote phrase' "double quote phrase"

From man bash

Words of the form $'string' are treated specially. The word expands to string, with backslash-escaped characters replaced as specified by the ANSI C standard. Backslash escape sequences, if present, are decoded as follows:

          \a     alert (bell)
          \b     backspace
          \e
          \E     an escape character
          \f     form feed
          \n     new line
          \r     carriage return
          \t     horizontal tab
          \v     vertical tab
          \\     backslash
          \'     single quote
          \"     double quote
          \nnn   the eight-bit character whose value is the octal value nnn (one to three digits)
          \xHH   the eight-bit character whose value is the hexadecimal value HH (one or two hex digits)
          \cx    a control-x character

In bash:

echo $'scan \'LPV\',{FILTER => "(PrefixFilter (\'MP1-Eq1\')"}'

or

echo "scan 'LPV',{FILTER => \"(PrefixFilter ('MP1-Eq1')\"}'"

For longer strings this may be a more convinient alternative:

> cat <<EOT
scan 'LPV',{FILTER => "(PrefixFilter ('MP1-Eq1')"}
EOT

with EOT or \EOT, depending on whether parameter expansion and quote removal (backslash) are intended or not.

Usage within awk

Defining this string within awk would make everything even more complex. This should be done outside awk in the shell:

ftable=$'echo "scan \'LPV\',{FILTER => "(PrefixFilter (\'MP1-Eq1\')"}"'
# echo "$ftable"
awk -v ftable="$ftable" '... system(ftable); ...'