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Printing output of c program to a file in Linux

Q. I’ve written a small program that does something useful for me. I always get output on screen. Sometime I need to send output to a file. How do I print output of my program to a file w/o making any changes to code?

A. Bash shell (and many other modern UNIX shell) supports the concept of I/O redirection It allows you to redirect standard output (screen), standard error and standard input (keyboard) using the following syntax.
command > output.file
command < input.file command >& error-n-output.file

So to redirect output of your own C program just enter:
$ ./myprogr > output.txt
$ cat output.txt

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{ 5 comments… add one }

  • sairam kunala August 18, 2007, 5:44 pm

    for redirecting stderr to a file

    command 2> error.file

  • sher October 27, 2007, 9:06 am

    offcourse this is very helpful document

  • soraver May 6, 2008, 12:40 pm

    in addition by using
    command >> file
    you can reuse the same file without deleting the previous data.
    >> adds text to the end of the file :)

  • aftab June 12, 2011, 4:38 am

    Thanks a lot for that,
    But is there a way i can write the output of a c program into a file from WITHIN THE PROGRAM. For example, i know this doesnt work, but what can i do to repliacte this

    system(“ls”) > t1.txt

  • prakash November 21, 2011, 6:45 am

    Thanks a lot dear ,

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