Using Variables with th 'System' command

This is a discussion on Using Variables with th 'System' command within the Linux Programming forums, part of the Platform Specific Boards category; Hi friends: I have a tiny problem. I want to graph some data i have stored in a file with ...

  1. #1
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    Using Variables with th 'System' command

    Hi friends:

    I have a tiny problem.
    I want to graph some data i have stored in a file with the RRDtool program. This RRDTooll program works with shell commands:
    rrdtool create test.rrd \
    --start 920804400 \
    DS:speed:COUNTER:600:U:U RRA \

    etc, etc

    Now, I want to make a C program to graph these data. But i don't know how to add variables with the system command
    system("rrdtool create test.rrd --start %s ...",a);

    How can i do that in C. or How could i do that in a shell script????

    Please Help me!
    A Man can be whatever he wants to
    be

  2. #2
    End Of Line Hammer's Avatar
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    Apr 2002
    Posts
    6,231
    Use a buffer to hold the string, something like:
    char buf[1024];
    Put you commands in there (maybe using strcpy(), sprintf() etc), then call system(buf);

    Alternatively, read the FAQ
    When all else fails, read the instructions.
    If you're posting code, use code tags: [code] /* insert code here */ [/code]

  3. #3
    Registered User
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    Sep 2003
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    Talking

    Thanks a lot
    A Man can be whatever he wants to
    be

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