## Substitution of system commands in backquotes

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 plot datafile special-filenames (p. ).

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`"