Hi Shamrock/fpmurphy,

I have changed the code using sprintf and is working fine and I have one more doubt with the output of the program now.

Code:

# include <stdio.h>
# include <stdlib.h>
# include <strings.h>

main(argc,argv)
int argc;
char *argv[];
{
int i;
/*char *cmd,*opt;*/
char cmd[1024];
printf("%d is arg\nc",argc);
printf("arg0 is %s\n",argv[0]);
printf("arg1 is %s\n",argv[1]);

if(argc!=2)
{
printf("usage Wrong");
exit(0);
}

printf("The command you ahve entered is %s\n",argv[1]);
printf("Let us display the various outputs for different options for the command");

i='a';
while(i>='a'&& i<='z')
{
printf("\n option is %d ASCII is %c",i,i);
sprintf(cmd,"%s -%c",argv[1],i);
system(cmd);
i++;
}

}


Output:

[ramki@lindesk3 ramki]$ ./cmd_opt ls
2 is arg
carg0 is ./cmd_opt
arg1 is ls
The command you ahve entered is ls
Let us display the various outputs for different options for the command
. .bash_history .bashrc db_cnnct_stps .gtkrc myshell sys_info xplrng_c
.. .bash_logout CCS .emacs hi.txt .mysql_history sysint_ex
ascii .bash_profile cmd_opt filename.sh .kde options_wth_exe_cmds.c .viminfo option is 97 ASCII is a
ascii CCS cmd_opt db_cnnct_stps filename.sh hi.txt myshell options_wth_exe_cmds.c sys_info sysint_ex xplrng_c
option is 98 ASCII is b
options_wth_exe_cmds.c hi.txt cmd_opt sysint_ex filename.sh db_cnnct_stps CCS xplrng_c myshell ascii sys_info
option is 99 ASCII is c
.
option is 100 ASCII is d
ls: invalid option -- e
Try `ls --help' for more information.
option is 101 ASCII is e
. .emacs .bashrc .viminfo .mysql_history cmd_opt xplrng_c CCS
.. .bash_logout .gtkrc myshell db_cnnct_stps filename.sh sys_info
.kde .bash_profile ascii .bash_history sysint_ex hi.txt options_wth_exe_cmds.c
option is 102 ASCII is f
total 52
-rw-r--r-- 1 users 1426 Mar 3 16:29 ascii
drwxr-xr-x 2 users 4096 Mar 13 15:55 CCS
-rwxr-xr-x 1 users 5434 Mar 24 10:09 cmd_opt
-rw-r--r-- 1 users 122 Mar 14 14:04 db_cnnct_stps
-rwxr--r-- 1 users 37 Mar 20 17:28 filename.sh
-rw-r--r-- 1 users 5698 Mar 24 10:20 hi.txt
drwxr-xr-x 2 users 4096 Mar 11 11:43 myshell
-rw-r--r-- 1 users 690 Mar 24 10:24 options_wth_exe_cmds.c
drwxr-xr-x 2 users 4096 Mar 3 12:23 sys_info
drwxr-xr-x 2 users 4096 Mar 20 17:47 sysint_ex
drwxr-xr-x 7 users 4096 Mar 12 15:35 xplrng_c
option is 103 ASCII is g
ascii CCS cmd_opt db_cnnct_stps filename.sh hi.txt myshell options_wth_exe_cmds.c sys_info sysint_ex xplrng_c
option is 104 ASCII is h
147745 ascii 148103 db_cnnct_stps 908434 myshell 908425 sysint_ex
908426 CCS 148232 filename.sh 148221 options_wth_exe_cmds.c 907491 xplrng_c
147812 cmd_opt 148142 hi.txt 908388 sys_info
option is 105 ASCII is i
ls: invalid option -- j
Try `ls --help' for more information.
option is 106 ASCII is j
ascii CCS cmd_opt db_cnnct_stps filename.sh hi.txt myshell options_wth_exe_cmds.c sys_info sysint_ex xplrng_c
option is 107 ASCII is k
total 52
-rw-r--r-- 1 ramki users 1426 Mar 3 16:29 ascii
drwxr-xr-x 2 ramki users 4096 Mar 13 15:55 CCS
-rwxr-xr-x 1 ramki users 5434 Mar 24 10:09 cmd_opt
-rw-r--r-- 1 ramki users 122 Mar 14 14:04 db_cnnct_stps
-rwxr--r-- 1 ramki users 37 Mar 20 17:28 filename.sh
-rw-r--r-- 1 ramki users 5698 Mar 24 10:20 hi.txt
drwxr-xr-x 2 ramki users 4096 Mar 11 11:43 myshell
-rw-r--r-- 1 ramki users 690 Mar 24 10:24 options_wth_exe_cmds.c
drwxr-xr-x 2 ramki users 4096 Mar 3 12:23 sys_info
drwxr-xr-x 2 ramki users 4096 Mar 20 17:47 sysint_ex
drwxr-xr-x 7 ramki users 4096 Mar 12 15:35 xplrng_c
option is 108 ASCII is l
ascii, CCS, cmd_opt, db_cnnct_stps, filename.sh, hi.txt, myshell, options_wth_exe_cmds.c, sys_info, sysint_ex, xplrng_c
option is 109 ASCII is m
total 52
-rw-r--r-- 1 578 100 1426 Mar 3 16:29 ascii
drwxr-xr-x 2 578 100 4096 Mar 13 15:55 CCS
-rwxr-xr-x 1 578 100 5434 Mar 24 10:09 cmd_opt
-rw-r--r-- 1 578 100 122 Mar 14 14:04 db_cnnct_stps
-rwxr--r-- 1 578 100 37 Mar 20 17:28 filename.sh
-rw-r--r-- 1 578 100 5698 Mar 24 10:20 hi.txt
drwxr-xr-x 2 578 100 4096 Mar 11 11:43 myshell
-rw-r--r-- 1 578 100 690 Mar 24 10:24 options_wth_exe_cmds.c
drwxr-xr-x 2 578 100 4096 Mar 3 12:23 sys_info
drwxr-xr-x 2 578 100 4096 Mar 20 17:47 sysint_ex
drwxr-xr-x 7 578 100 4096 Mar 12 15:35 xplrng_c
option is 110 ASCII is n
total 52
-rw-r--r-- 1 ramki 1426 Mar 3 16:29 ascii
drwxr-xr-x 2 ramki 4096 Mar 13 15:55 CCS
-rwxr-xr-x 1 ramki 5434 Mar 24 10:09 cmd_opt
-rw-r--r-- 1 ramki 122 Mar 14 14:04 db_cnnct_stps
-rwxr--r-- 1 ramki 37 Mar 20 17:28 filename.sh
-rw-r--r-- 1 ramki 5698 Mar 24 10:20 hi.txt
drwxr-xr-x 2 ramki 4096 Mar 11 11:43 myshell
-rw-r--r-- 1 ramki 690 Mar 24 10:24 options_wth_exe_cmds.c
drwxr-xr-x 2 ramki 4096 Mar 3 12:23 sys_info
drwxr-xr-x 2 ramki 4096 Mar 20 17:47 sysint_ex
drwxr-xr-x 7 ramki 4096 Mar 12 15:35 xplrng_c
option is 111 ASCII is o
ascii CCS/ cmd_opt db_cnnct_stps filename.sh hi.txt myshell/ options_wth_exe_cmds.c sys_info/ sysint_ex/ xplrng_c/
option is 112 ASCII is p
ascii CCS cmd_opt db_cnnct_stps filename.sh hi.txt myshell options_wth_exe_cmds.c sys_info sysint_ex xplrng_c
option is 113 ASCII is q
xplrng_c sysint_ex sys_info options_wth_exe_cmds.c myshell hi.txt filename.sh db_cnnct_stps cmd_opt CCS ascii
option is 114 ASCII is r
total 52
4 ascii 8 cmd_opt 4 filename.sh 4 myshell 4 sys_info 4 xplrng_c
4 CCS 4 db_cnnct_stps 8 hi.txt 4 options_wth_exe_cmds.c 4 sysint_ex
option is 115 ASCII is s
options_wth_exe_cmds.c hi.txt cmd_opt sysint_ex filename.sh db_cnnct_stps CCS xplrng_c myshell ascii sys_info
option is 116 ASCII is t
cmd_opt options_wth_exe_cmds.c hi.txt CCS myshell sys_info sysint_ex xplrng_c ascii filename.sh db_cnnct_stps
option is 117 ASCII is u
CCS ascii cmd_opt db_cnnct_stps filename.sh hi.txt myshell options_wth_exe_cmds.c sys_info sysint_ex xplrng_c
option is 118 ASCII is v
ls: option requires an argument -- w
Try `ls --help' for more information.
option is 119 ASCII is w
ascii CCS cmd_opt db_cnnct_stps filename.sh hi.txt myshell options_wth_exe_cmds.c sys_info sysint_ex xplrng_c
option is 120 ASCII is x
ls: invalid option -- y
Try `ls --help' for more information.
option is 121 ASCII is y
ls: invalid option -- z
Try `ls --help' for more information.
option is 122 ASCII is z


ACtually the "option is 97 ASCII is a" has to be printed first and then its output ". .bash_history .bashrc db_cnnct_stps .gtkrc myshell sys_info xplrng_c
.. .bash_logout CCS .emacs hi.txt .mysql_history sysint_ex
ascii .bash_profile cmd_opt filename.sh .kde options_wth_exe_cmds.c .viminfo"

I experienced the same thing with another C program.. Where the unix system call [which has been called 5 times in a while loop] output is printed first and then the output of printf 5 times gets printed [printf is used preceding to the unix system vall in that particular program] . Are the unix system calls functions that much faster so that the sequence of program written is not followed?

Please explain.

Thanks,
Ramkrix