Unix backquote

The backquote ` is used for command substitution.

When the shell encounters a string between backquotes `cmd` it executes cmd and replaces the backquoted string with the standard output of cmd, with any trailing newlines deleted.

PriceLine=`grep $symbol $pricefile | sed 's/^[A-Z]\{1,\}//'`

set `echo ${PriceLine}`

Bourne shell uses three characters for quoting: single quotes ('), double quotes ("), and backslashes (\).

• A backslash (\) protects the next character, except if it is a newline. If a backslash precedes a newline, it prevents the newline from being interpreted as a command separator, but the backslash-newline pair disappears completely.

• Single quotes ('...') protect everything (even backslashes, newlines, etc.) except single quotes, until the next single quote.

• Double quotes ("...") protect everything except double quotes, backslashes, dollar signs, and backquotes, until the next double quote. A backslash can be used to protect ", \, $, or ` within double quotes. A backslash-newline pair disappears completely; a backslash that does not precede ", \, $, `, or newline is taken literally.