Linux only C function help

[Leo TS]

Hello,

I just started writing code for Linux. I have been writing code for DOS, and Windows for years. I am looking for something that will assist in writing C/C++ code for Linux, especially Linux only commands (i.e. function to get domain, and logged on user). Also, what app is best to find text strings inside of files in linux. In Windows there is the find function, but I can't find anything that will do the same in Linux.

Thanks for the assistance.

[CaptainPinko]

isn't there a system() sub that will just send a string to the shell? you could then just use "whoami" etc.

[CaptainPinko]

just looked it up it's the SYSTEM(3) call. It's from stdlib.h. Just do a man system and look'er up.

I would system (&"whoami > ./iam.txt"); and then just open the file iam.txt read from it and delete the file. It is a bit of a hack but it should work.

[Fryguy8]

a bit of a hack!? man that **** is ugly :)

[duncanbojangles]

Originally posted by Leo TS
Also, what app is best to find text strings inside of files in linux. In Windows there is the find function, but I can't find anything that will do the same in Linux.

Thanks for the assistance.

grep. Grep is your friend: Just type in "man grep" at your shell.

[mwinterberg]

^^^ dang it, that's what I get for trying to find getpwuid

grep(1) will be the best to find text strings inside of files.

To get logged on user would be a two-step process:
first:
getuid(2)
Then:
getpwuid(3)
(I think... it's available on Solaris and FreeBSD, so here's hopin').

Using apropos(1) will be one of your best resources for finding out how to get most of the items. Man pages in sections 2 and 3 will be most helpful.

Just to cover everything, man page sections are shown in parens after the name of the command. So, for example getuid(2) is in section 2, system(3) (from CaptainPinko) is in section 3, and apropos(1) is in section 1.

[chrism01]

Note that the cmd option to specify a section of the man pages is only required if a reference exists in more than one section and would look like :

man 2 getuid

otherwise
man getuid

is suffcient.

HTH

[jim mcnamara]

There are several very good books on Unix programming (There is no such thing as a Linux-only api like there is in Windoze for NT and XP)

In Unix there are system calls - this book does a good job

Marc Rochkind 'Advanced UNIX Programming'

Also see:
http://www.advancedlinuxprogramming.com/

Lets you download a free pdf-format book that covers a lot of material.

For general topics like using Unix commands

www.tldp.org

[bwkaz]

If you want to read the output of a command that you run:

http://www.justlinux.com/forum/showthread.php?s=&postid=301819#post301819

illustrates a VERY good way of doing it. In the default case on the switch, the parent just reads from fd[0] to get the text that the child is printing out.

To figure out what's going on, most of the system calls here are in section 2 of the manpages. There is also read(2) and write(2), if you need them.