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Command-line substitution is specified by a system command enclosed in backquotes. This command is spawned and the output it produces replaces the backquoted text 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`"