Command-line substitution is specified by a system command enclosed in backquotes. This command is spawned and the output it produces replaces the name of the command (and backquotes) on the command line. Some implementations also support pipes; see special-filenames.
Command-line substitution can be used anywhere on the `gnuplot` command line, except inside strings delimited by single quotes.
Example:
This will run the program `leastsq` and replace `leastsq` (including backquotes) on the command line with its output:
f(x) = `leastsq`
or, in VMS
f(x) = `run leastsq`
These will generate labels with the current time and userid:
set label "generated on `date +%Y-%m-%d`by `whoami`" at 1,1 set timestamp "generated on %Y-%m-%d by `whoami`"