hey i tried to install flex and bison in ubantu 9.10 but i am not able to install it properly even though i follow the steps
when i used
./configure
i got these errors
ng for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for gawk... no
checking for mawk... mawk
checking whether make sets $(MAKE)... yes
checking for style of include used by make... GNU
checking for gcc... gcc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables...
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ANSI C... none needed
checking dependency style of gcc... gcc3
checking how to run the C preprocessor... gcc -E
checking for egrep... grep -E
checking for AIX... no
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for unistd.h... yes
checking minix/config.h usability... no
checking minix/config.h presence... no
checking for minix/config.h... no
checking whether it is safe to define __EXTENSIONS__... yes
checking for gcc... (cached) gcc
checking whether we are using the GNU C compiler... (cached) yes
checking whether gcc accepts -g... (cached) yes
checking for gcc option to accept ANSI C... (cached) none needed
checking dependency style of gcc... (cached) gcc3
checking for gcc... (cached) gcc
checking whether we are using the GNU C compiler... (cached) yes
checking whether gcc accepts -g... (cached) yes
checking for gcc option to accept ANSI C... (cached) none needed
checking dependency style of gcc... (cached) gcc3
checking for flex... no
checking for lex... no
checking for yywrap in -lfl... no
checking for yywrap in -ll... no
checking for bison... no
checking for byacc... no
checking for ranlib... ranlib
checking for gm4... no
checking for gnum4... no
checking for m4... no
checking whether m4 supports frozen files... no
configure: error: GNU M4 1.4 is required


and when i used
sudo apt-get install bison flex
i got these errors

Reading package lists... Done
Building dependency tree
Reading state information... Done
Package flex is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package flex has no installation candidate

i am new to linux pls help.....

Ubuntu 9.10 is end of life and totally unsupported. I strongly recommend to install a supported version, so that you get bugfixes and, more important, security updates again. this way you will also be able again to use the package management system to install software.

Welcome to LQ.

If you really want to use the old obsolete Ubuntu 9.10 Karmic,
the text in /etc/apt/sources.list must be repaced with :
I.e. : sudo gedit /etc/apt/sources.list
And next update the package list with : sudo apt-get-update

.