SQL runs bash scripts or commands

bash

-- Run a bash command or script.
-- It assumes bash is installed by YUM so 
-- it will be in the default location /QOpenSys/pkgs/bin/bash
-- You can use this aproach to other shells like sh, qsh setc.
-- I use qusrsys here however I suggest that you use your own toolibrary
-- you need library QSYSINC installed:
-- https://www.ibm.com/support/knowledgecenter/ssw_ibm_i_74/apiref/conQSYSINC.htm
-- I doubt this method is a good idea to build huge applications, 
-- however it is a cool example how far you can go with SQL:
----------------------------------------------------------------------------------------------
call qcmdexc ('addlible qsysinc');
call qcmdexc ('crtsrcpf FILE(QTEMP/C) MBR(C)');
delete  from qtemp.c;
insert into qtemp.c (srcdta) values 
    ('{'),
    ('#include <QP2SHELL.h>'), 
    ('BASH.COMMAND.DAT[BASH.COMMAND.LEN] = 0;'),
    ('QP2SHELL ("/QOpenSys/pkgs/bin/bash" , "-c" , BASH.COMMAND.DAT);'),
    ('}')
;

create or replace procedure qusrsys.bash (command varchar(32700) )
no external action 
set option output=*print, commit=*none, dbgview = *source
begin 
    include qtemp/c(c);
end;   

-- And a polymorph version to return a CLOB from STDOUT
-- (This is just a simple implementation - stay tuned) 
create or replace function qusrsys.bash (
    command varchar(32700), 
    ccsid   int default 1252
) 
returns clob
no external action 
modifies sql data
set option output=*print, commit=*none, dbgview = *source
begin atomic
    declare retval clob;
    declare tmpfile varchar(256);
    set tmpfile = '/tmp/x' || translate( char(now()), '--' , '.:');   
    call qusrsys.bash (command || '&>' || tmpfile || ';setccsid ' || ccsid || ' ' || tmpfile);
    set retval = GET_CLOB_FROM_FILE(tmpfile);
    call qusrsys.bash ('rm ' || tmpfile);
    return retval; 
end;    


stop; 
-- Test and usecase from here:
------------------------------

-- Test it like this 
-- 1) makes nested directories from SQL:
call qusrsys.bash ('mkdir -p /a/b/c/d');

-- 2) List home directory
values ( 
    qusrsys.bash ('ls /home')
);

-- 3) List home directory, by a script in the command. note the commands are separated by ;
values (
    qusrsys.bash ('cd /home;ls')
);
--4) Get weather data using curl. 
--   This works where SYSTOOLS.HTTPGETCLOB fails if you have another PASE process running 
---  ( Only one PASE pr. job limitation)   
values (
  bash('curl -sS -k --url "https://www.dmi.dk/NinJo2DmiDk/ninjo2dmidk?cmd=llj&id=2618425&tz=Europe/Copenhagen"', 1208)
);

--4) Now combined and used as relational data with json_table
select jt.*
from 
json_table (
    bash('curl -sS -k --url "https://www.dmi.dk/NinJo2DmiDk/ninjo2dmidk?cmd=llj&id=2618425&tz=Europe/Copenhagen"',1208),
    '$.timeserie'
    columns (
        sampletime  char(14)    path '$.time',
        precipType  varchar(16) path '$.precipType',
        temerature  double      path '$.temp',
        windspeed   double      path '$.windSpeed', 
        winddegree  double      path '$.windDegree', 
        humidity    double      path '$.humidity', 
        pressure    double      path '$.pressure', 
        visibility  double      path '$.visibility'
    )
) as jt;