Dear All I occasionally found that the following script responds an error. It seems that "show" command is not consistent with the "If" condition. It works well when I change to "scalar plot=1." I can replicate this in gretl 1.9.12 under XP and gretl 1.9.12cvs under ubuntu 10.04. Thanks. Yi-Nung Yang Associate Professor Dept. if IB, CYCU, Taiwan. <hansl> open data3-6 ols Ct const Yt series uhat=$uhat scalar plot=0 if plot=1 fig1 <- gnuplot uhat --time-series --with-lines fig1.show endif </hansl> gretl version 1.9.12 Current session: 2013-04-12 01:25 ? open data3-6 Read datafile C:\Program Files\gretl\data\data3-6.gdt periodicity: 1, maxobs: 36 observations range: 1959 to 1994 Listing 3 variables: 0) const 1) Ct 2) Yt ? ols Ct const Yt Model 1: OLS, using observations 1959-1994 (T = 36) Dependent variable: Ct ... ... ? series uhat=$uhat Generated series uhat (ID 3) ? scalar plot=0 Generated scalar plot = 0 ? if plot=1 ? fig1 <- gnuplot uhat --time-series --with-lines ? fig1.show fig1: no such object Error executing script: halting