Re: [Gnuplot-info] 回?: 回?: system command in gnuplot

[Andrew R. <an...@gm...>]

You can definitely pass arguments to a bash script. In the script, you use
the arguments as variables $1, $2, etc. (Reference example:
https://www.golinuxcloud.com/beginners-guide-to-use-script-arguments-in-bash-with-examples/
).

It will take some fiddling to construct the command in gnuplot, but if the
variables are var1 and var2 for example, you can do it like this:

> system("bash -c ./myscript.sh ".var1." ".var2)

The '.' concatenates the string variables. If var1 or var2 is a number like
16.0 instead of a string "16.0", you might have to do something like the
below with sprintf to get it to turn into a string correctly:

> system("bash -c ./myscript.sh ".var1." ".sprintf("%.1f", var2))

Andy

On Tue, Dec 29, 2020 at 12:48 AM qin...@st... <
qin...@st...> wrote:

> Dear Andy
>
> As your advice, we can reduce syntax / escape errors by put the paste /
> awk script in a separate file ("myscript.sh").
>
> Then call it from inside gnuplot as plot "< bash ./myscript.sh"
>
> But if the data  file name (Q_byE_i*.txt) is a string variable and “16.0”
> of  “if($1==16.0”  in awk part is also a variable,
>
> How can I pass these variables from gnuplot into myscript.sh.
>
>
>
> Because I'm not very familiar with linux, my questions might be very basic
> or stupid.
>
> please forgive me.
>
> ****************************************************
> 秦志豪
> 京都大学大学院 エネルギー科学研究科
> エネルギー基礎科学専攻 プラズマ・核融合基礎学分野
> 岸本研究室
> E-mail : qin...@st...
> ****************************************************
>
>
>
> *发件人: *Andrew Rasmussen <an...@gm...>
> *发送时间: *2020年12月29日 1:13
> *收件人: *qin...@st...
> *抄送: *gnu...@li...
> *主题: *Re: 回?: [Gnuplot-info] system command in gnuplot
>
>
>
> Yes, you should be able to make a similar modification, something like:
>
>
>
> plot "< bash -c 'paste  <(cat Q_byE_i*.txt) <(cat Q_byM_i*.txt)|awk
> \'{if($1==16.0) { e[$3] += $4 }}END { for ( i in e) { print i , e[i]}}\''"
>
>
>
> I can't test it out, so you might have to escape some additional
> characters (* etc.).
>
>
>
> When you are using a command that is this complicated, a way to simplify
> things and reduce syntax / escape errors is to put the paste / awk script
> in a separate file ("myscript.sh") and call that script from inside gnuplot:
>
>
>
> plot "< bash ./myscript.sh"
>
>
>
> Andy
>
>
>
> On Mon, Dec 28, 2020 at 9:31 AM qin...@st... <
> qin...@st...> wrote:
>
> Dear Andy
>
>
>
> Thank you very much.
>
> It worked. But I have another question.
>
> In fact, I tried to merge some data files, then plot a graph.
>
> The code is
>
> plot "< paste  <(cat Q_byE_i*.txt) <(cat Q_byM_i*.txt)|awk '{if($1==16.0)
> { e[$3] += $4 }}END { for ( i in e) { print i , e[i]}}'"  u 1:2
>
>
>
> The latter part of code about ‘awk’, I think there is no problem. Could I
> modify the code as the system("bash -c 'paste <(ls Q*) <(ls F*)'")?
>
>
>
> Qin
>
>
>
> ****************************************************
> 秦志豪
> 京都大学大学院 エネルギー科学研究科
> エネルギー基礎科学専攻 プラズマ・核融合基礎学分野
> 岸本研究室
> E-mail : qin...@st...
> ****************************************************
>
>
>
> *发件人: *Andrew Rasmussen <an...@gm...>
> *发送时间: *2020年12月28日 23:57
> *收件人: *qin...@st...
> *抄送: *gnu...@li...
> *主题: *Re: [Gnuplot-info] system command in gnuplot
>
>
>
> Hello,
>
>
>
> Your error comes from the fact that gnuplot is running the system command
> using the sh shell instead of bash (or whatever your usual shell is). You
> can get the command to be interpreted by bash like this:
>
>
>
> system("bash -c 'paste <(ls Q*) <(ls F*)'")
>
>
>
> Andy
>
>
>
> On Mon, Dec 28, 2020 at 4:11 AM qin...@st... <
> qin...@st...> wrote:
>
> Hello
>
> Now I am using gnuplot (Version 5.2 patchlevel 6) on a Linux system.
> The information of operating system as follow
> Linux version 4.4.162-94.72-default (geeko@buildhost) (gcc version 4.8.5
> (SUSE Linux) )
> LSB Version:    n/a
> Distributor ID: SUSE
> Description:    SUSE Linux Enterprise Server 12 SP3
> Release:        12.3
> Codename:       n/a
>
> My question:
>  I am trying to launch a system command in gnuplot like
> Terminal type is now 'qt'
> gnuplot> system(" paste <(ls Q*) <(ls F*)")
>
> show me the error message as
> sh: -c: line 0: syntax error near unexpected token `('
> sh: -c: line 0: ` paste <(ls Q*) <(ls F*)'
>
> But if I exit the gnuplot and run the command, it can work.
> qin@csc1:~/qin /txt> paste <(ls Q*) <(ls F*)
>
> any help would be much appreciated
> have a nice day
>
> ****************************************************
> 秦志豪
> 京都大学大学院 エネルギー科学研究科
> エネルギー基礎科学専攻 プラズマ・核融合基礎学分野
> 岸本研究室
> E-mail : qin...@st...
> ****************************************************
>
>
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