shell script Question

Whiteghost · 09-25-2005, 07:30 PM

My question is how do i get the c headers in a shell script to work?I have seen some shell script with headers in it.I ope someone can help me with this question.

jailbait · 09-25-2005, 08:10 PM

"My question is how do i get the c headers in a shell script to work?I have seen some shell script with headers in it."

Shell scripts do not support C headers. The closest thing in script programming to what you describe is functions. Here is some documentation which describes how to use functions in bash script programs.

Bash-Scripting Guide
http://www.tldp.org/LDP/abs/html/

explanation of functions:
http://www.tldp.org/LDP/abs/html/functions.html

function examples:
http://www.tldp.org/LDP/Bash-Beginne...ect_11_02.html

-----------------------
Steve Stites

Whiteghost · 09-25-2005, 09:01 PM

This what i talking about..

if [ ".`whoami`" != ".root" ]; then
echo "you had to be root to do this!"
exit 1
fi

echo "Now creating socket demon in " $HIDE

echo "#define PORT " $PORT > socketdemon.c
cat >>socketdemon.c <<'EOF'
#include <stdio.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

jailbait · 09-25-2005, 09:56 PM

"#include <stdio.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>"

Any line that begins with a # is a comment and that line is ignored by bash.

------------------------
Steve Stites

paulsm4 · 09-25-2005, 10:05 PM

The snippet you posted seems to be a shell script that creates part of a C source file:

Code:

if [ ".`whoami`" != ".root" ]; then
  echo "you had to be root to do this!"
  exit 1
fi
  <= THIS IS PURE SHELL: IT CHECKS TO SEE IF THE CURRENT USER IS "ROOT"

echo "Now creating socket demon in " $HIDE
  <= THIS, TOO, IS PURE SHELL: IT PRINTS OUT THE TEXT ("Now creating..."), FOLLOWED
        BY THE VALUE OF THE SHELL VARIABLE "$HIDE".
        VARIABLES "HIDE" AND "PORT" WERE BOTH  SET SOMEWHERE ELSE
echo "#define PORT " $PORT > socketdemon.c
cat >>socketdemon.c <<'EOF'
#include <stdio.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
  <= THIS CAUSES THE REST OF THE SCRIPT TO BE WRITTEN VERBATIM INTO THE
        FILE "SOCKETDEMON.C"

The syntax "<<'EOF'" is called a "here script". You can read more about them in the link jailbait pointed out:
http://www.tldp.org/LDP/abs/html/here-docs.html