Wednesday, August 15, 2007

Programming C under Unix

Writing a test Program in C (Unix):
====================================
[root@linuxbox C_Programs]# cat test.c
#include
main()
{

printf ("Hello Sriram!!\n");

return 0;

}

Executing the above :
=====================
[root@linuxbox C_Programs]# gcc test.c

[root@linuxbox C_Programs]# ls
a.out test.c

[root@linuxbox C_Programs]# ./a.out
Hello Sriram!!

Find command tips ...

Finding Max space used by Top 10 Files in MB:
============================================

[root@linuxbox Desktop]# find /tmp -type f | xargs ls -msa
| sort -rn | awk '{size=$1/1024;printf("%dMb %s\n", size,$2);}'
| head

10Mb /tmp/openldap-devel-2.3.34-0.fc7.i386.rpm,
6Mb /tmp/newtonslaw.wav
4Mb /tmp/openldap-clients-2.3.34-0.fc7.i386.rpm,
3Mb /tmp/ntfs-3g-1.516-1.fc7.i386.rpm,
2Mb /tmp/fuse-2.6.5-1.fc7.i386.rpm,
1Mb /tmp/orbit-root/bonobo-activation-server-ior,
0Mb /tmp/gconfd-root/lock/ior,
0Mb /tmp/orbit-root/bonobo-activation-register.lock,

Finding files which are more than 10 MB:
========================================

find /tmp -name "*" -size +10000k

Finding files modified 3 days ago but less than 5 days:
========================================================

find /tmp -type f -mtime +2 -mtime -5


Find files that were accessed exactly 3 days a go
==================================================
find /tmp -type f -atime 3


-atime +7: All files that were last accessed more than 7 days ago
-atime 7: All files that were last accessed exactly 7 days ago
-atime -7: All files that were last accessed less than7 days ago

To replace recursive in *.html files, with multiline support:
=============================================================
find ./dir/ -name *.html -exec perl -pi -e 'undef $/;
s/REPLACE-THIS/WITH-THAT/s' {} \;

Update the modification date for all files in the
current directory and below:
=================================================
find . -exec touch {} \;

Remove files in a directory that were created more
than x number of days ago (great for managing Maildir).
======================================================
find ./ -ctime +x | xargs | rm -f -r

This should delete files older than 7 days, and
print the name of each file it deletes.
=================================================
find ./ -ctime +7 -name "*.zip" -exec rm -f {} \; -ls

# If you want to be prompted before it deletes a file:
find ./ -ctime +7 -name "*.zip" -exec rm -i {} \; -ls

This will list the files with names ending in .c
and containing the word hello:
=================================================

find . -type f -name '*.c' -exec grep -l hello {} /dev/null \;

Find all the files recursively that contain foo:
================================================
find . | xargs grep foo
./a:foo
./c:foo
./d:ifoo

a,c,d are the file names that contain foo

Mounting Windows NTFS partition under Fedora 7

I have a dual boot Fedora 7 + Windows 2000 Pro

When I tried mounting the NTFS Partition


# mount /dev/hda1 /mnt/win
mount: unknown filesystem type 'ntfs'

I got the above message.

Then this is what I did to Mount windows NTFS partition
Under Fedora Release 7(Moonshine):

Install the below packages from Fedora core 7 DVD

rpm -ivh fuse-2.6.5-1.fc7.i386.rpm
rpm -ivh fuse-libs-2.6.5-1.fc7.i386.rpm
rpm -ivh ntfs-3g-1.516-1.fc7.i386.rpm

[root@linuxbox tmp]# fdisk -lu

Disk /dev/sda: 40.0 GB, 40007761920 bytes
255 heads, 63 sectors/track, 4864 cylinders,
total 78140160 sectors
Units = sectors of 1 * 512 = 512 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 63 51199154 25599546 7 HPFS/NTFS
/dev/sda2 51199155 51407999 104422+ 83 Linux
/dev/sda3 51408000 78140159 13366080 8e Linux LVM


My Windows NTFS partition is /dev/sda1

I create a directory
#mkdir /mnt/win_c/

Then Mount it:
[root@linuxbox tmp]# mount -t ntfs-3g /dev/sda1 /mnt/win_c/

[root@linuxbox win_c]# pwd
/mnt/win_c

[root@linuxbox win_c]# ls
arcldr.exe hawkz.exe RECYCLER
arcsetup.exe hiberfil.sys S4uDi.exe
AUTOEXEC.BAT IO.SYS Songs
boot.ini MSDOS.SYS Sriram
citianywhere.log My Music swsetup
citrix.log NTDETECT.COM System Volume Information
CONFIG.SYS ntldr WINNT
Documents and Settings pagefile.sys YServer.txt
Ebooks Program Files