diff options
Diffstat (limited to '1088/CH24/EX24.8')
| -rwxr-xr-x | 1088/CH24/EX24.8/Example8.sce | 72 | ||||
| -rwxr-xr-x | 1088/CH24/EX24.8/Result8.txt | 84 |
2 files changed, 156 insertions, 0 deletions
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) + + diff --git a/1088/CH24/EX24.8/Result8.txt b/1088/CH24/EX24.8/Result8.txt new file mode 100755 index 000000000..f2bbe3421 --- /dev/null +++ b/1088/CH24/EX24.8/Result8.txt @@ -0,0 +1,84 @@ + ans =
+
+ 1.
+
+-->exec('Example8.sci')
+
+-->clear
+
+-->flag=1
+ flag =
+
+ 1.
+
+-->mode(-1)
+Current date is 23-Jun-2013
+
+Welcome to the Textbook Companionship Project 2013
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+ Book Title : UNIX CONCEPTS AND APPLICATIONS
+
+ Book Edition : 4
+
+ Book Author : Sumitabha Das
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+ Code Author : Pranav Bhat T
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+ Chapter Number : 24
+
+ Chapter Title : Systems programming II- Files
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+Example 8 : Show the effect of using the exec command to run a unix command
+
+ ****************************************************************
+
+ Answer :
+
+ INSTRUCTIONS :
+
+ 1.These programs are part of systems programming PURELY in Unix and the commands have NO EQUIVALENT IN SCILAB
+
+ 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
+
+ 3.The outputs displayed here are just MOCK OUTPUTS which are DISPLAYED IN THE TEXTBOOK
+
+ 4.The inconvenience is regretted.
+.............Press [ENTER] to continue..... UNIX SHELL SIMULATOR(DEMO VERSION WITH PRELOADED COMMANDS)
+
+
+
+
+$ cat exec_and_fork.c # to open the file emp.lst /* Program: exec_and_fork.c -- Uses fork, exec and wait to run a unix command */
+#include <stdio.h>
+#include <wait.h>
+
+int main(int argc,char **argv) {
+ int returnval; /* Used by wait*/
+
+ switch(fork()) {
+ case 0: /* Run command in child */
+ if ((exec(argv[1], &argv[2]) < 0 )) {
+ fprintf(stderr, "execl error\n");
+ exit(200);
+ }
+ default: /* In the parent */
+ wait(&returnval); /* After the command has completed .. */
+ fprintf(stderr,"Exit status: %d\n",WEXITSTATUS(returnval));
+ exit(0);
+ }
+}
+ $ cc exec_and_fork.c $ a.out /bin/grep grep -i -n SUMIT /etc/passwd 15:sumit:x:102:10::/users1/home/staff/sumit:/usr/bin/bash
+Exit status: 0
+
+
+$ exit #To exit the current simulation terminal and return to Scilab console
+
+........# (hit [ENTER] for result)
+
+ BACK TO SCILAB CONSOLE...
+Loading initial environment
+-->diary(0)
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