Important and useful Linux and Unix commands

TAGS: linux, unix, commands

Here are some commands that you may find useful while installing or troubleshooting Linux.

General Commands

How to write a boot image from your hard disk to a floppy

dd if=boot.img of=/dev/fd0

How to copy the boot image from your hard disk to a floppy

dd if=/dev/fd0 of=floppy.img

How to search for a file arul.jpg recursively in your Unix account

find ~/ -name "arul.jpg"

How to display all the processes running on the host

ps -af

How to check the current quota and tell how much you have used

quota

How to check disk space in a directory (say /usr)

du -s -H /usr

How to report size (in kBytes) of all enclosed directories (recursive)

du -k

How to report size (in kBytes) of all enclosed directories (non-recursive)

du -ms *

How to list login IDs of users currently logged in to the system

users

How to change the permanent information kept by the system about your logon ID

chfn

Administrator commands

access a windows (only FAT or FAT32) partition (say hda2) under linux

mount -t vfat /dev/hda2 /win

allow root user and other users(where user id=500) to get rw permission for that windows partition

mount -t vfat -o uid=500 /dev/hda2 /win

list all device files corresponding to hda

fdisk -l /dev/hda

track down symbolic links, for example, to see where xterm points to

namei /usr/X11/bin/xterm

print Linux version information

uname -r

measure hard disk speed

hdparm -tT /dev/hda

print hardware summary

more /proc/cpuinfo

check inode usage of all mounted partitions

df -i

monitoring the system for the growth of a file

tail -f /var/log/messages

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Last Update: Late 2004