From b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b Mon Sep 17 00:00:00 2001
From: priyanka
Date: Wed, 24 Jun 2015 15:03:17 +0530
Subject: initial commit / add all books

---
 1088/CH24/EX24.8/Example8.sce | 72 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100755 1088/CH24/EX24.8/Example8.sce

(limited to '1088/CH24/EX24.8/Example8.sce')

diff --git a/1088/CH24/EX24.8/Example8.sce b/1088/CH24/EX24.8/Example8.sce
new file mode 100755
index 000000000..4e8eb6dd2
--- /dev/null
+++ b/1088/CH24/EX24.8/Example8.sce
@@ -0,0 +1,72 @@
+clear
+flag=1
+mode(-1)
+clc
+
+printf("Example 8    :    Show the effect of using the exec command to run a unix command \n")
+disp("****************************************************************")
+disp("Answer    :   ")
+disp("INSTRUCTIONS   : ")
+halt(' ')
+disp("1.These programs are part of systems programming PURELY in Unix and the commands have NO EQUIVALENT IN SCILAB")
+halt(' ')
+disp("2.However the .c files which are displayed here are also made into a seperate file.If you are a unix user then try compiling and running the programme with gcc or cc compiler")
+halt(' ')
+disp("3.The outputs displayed here are just MOCK OUTPUTS which are DISPLAYED IN THE TEXTBOOK")
+halt(' ')
+disp("4.The inconvenience is regretted.")
+halt('.............Press [ENTER] to continue.....')
+halt("")
+clc
+printf("\tUNIX SHELL SIMULATOR(DEMO VERSION WITH PRELOADED COMMANDS)\n\n\n")
+i=0
+i=i+1;f(i)='/* Program: exec_and_fork.c -- Uses fork, exec and wait to run a unix command */'
+i=i+1;f(i)='#include <stdio.h>'
+i=i+1;f(i)='#include <wait.h>'
+i=i+1;f(i)=''
+i=i+1;f(i)='int main(int argc,char **argv) {'
+i=i+1;f(i)='    int returnval;           /* Used by wait*/'
+i=i+1;f(i)='    '
+i=i+1;f(i)='    switch(fork()) {'
+i=i+1;f(i)='          case 0:           /* Run command in child */'
+i=i+1;f(i)='          if ((exec(argv[1], &argv[2]) < 0 )) {'
+i=i+1;f(i)='              fprintf(stderr, '+ascii(34)+'execl error\n'+ascii(34)+');'
+i=i+1;f(i)='              exit(200);'
+i=i+1;f(i)='              }'
+i=i+1;f(i)='          default:              /* In the parent */'
+i=i+1;f(i)='             wait(&returnval);  /* After the command has completed .. */'
+i=i+1;f(i)='             fprintf(stderr,'+ascii(34)+'Exit status: %d\n'+ascii(34)+',WEXITSTATUS(returnval));'
+i=i+1;f(i)='             exit(0);'
+i=i+1;f(i)='             }'
+i=i+1;f(i)='}'
+n=i
+
+    
+
+printf("\n\n$ cat exec_and_fork.c      # to open the file emp.lst")
+halt(' ')
+u=mopen('exec_and_fork.c','wt')
+for i=1:n
+    mfprintf(u,"%s\n",f(i))
+    printf("%s\n",f(i))
+end
+mclose(u)
+halt('')
+clc
+
+halt(' ')
+ printf("$ cc exec_and_fork.c")
+ halt(' ')
+ printf("$ a.out   /bin/grep   grep   -i -n  SUMIT   /etc/passwd                   ")
+ halt(' ')
+ printf("15:sumit:x:102:10::/users1/home/staff/sumit:/usr/bin/bash\nExit status: 0")
+ halt(' ')
+
+printf("\n\n\n$ exit        #To exit the current simulation terminal and return to Scilab console\n\n")
+halt("........# (hit [ENTER] for result)")
+//clc()
+
+printf("\n\n\t\t\tBACK TO SCILAB CONSOLE...\nLoading initial environment')
+sleep(1000)
+
+
-- 
cgit