Tag Archives: unix

How to Remove ^M in Linux & Unix

Control M ( ^M)  characters are introduced when you use  lines of text from a windows computer to  Linux or Unix machine.  Most common reasons are when you directly copy a file from a windows system or submit form data copied and pasted from a windows machine.

Detecting ^M characters

^M is non printable character and often becomes difficult to find, in order to see if your file contains any non printable character use the cat command with -v option

$cat -v filename

Methods to remove ^M

In all these method , real secret is not to type ^M using keyboard but rather typing in control key sequence to get the ^M control character.

man command in Linux and Unix

man command, short for manual, provides help for the commands, utilities or function in Linux and Unix systems. Learn about usage , related packages, sections and other interesting facts about man pages.

Top 10 Must have Books for Unix and Linux

Here is the top 10 must have books for Unix and Linux , these are great books for any one working in Unix and Linux from beginner to advance users  improve skills and go deeper to understand, learn, program and manage Unix and Linux systems.

vi editor Quick Reference & Cheat Sheet



Learn about the default text editor, vi, pronounced as ”vee eye”, in Unix, Linux and other Unix like systems. A short, concise vi quick reference lets you get started with vi today. Explains vi editor mode &  vi commands with examples for editing in vi.  Click to download and print  vi editor Cheat Sheet  in PDF format.

fsck – Check & Repair Unix and Linux File Systems

fsck, similar to chkdsk in windows, checks and repairs the file system in Unix & Linux operating systems. Learn about fsck modes, phases & fsck errors messages

fsck, File System Consistency checK, is a system utility in Unix, Linux and other Unix like systems for checking and repairing file system inconsistencies.

File system can become inconsistent due to several reasons and the most common is abnormal shutdown due to hardware failure, power failure or switching off the system without proper shutdown. Due to these reasons the superblock in a file system is not updated and has mismatched information relating to system data blocks, free blocks and inodes.

fsck in Linux

fsck in this document is refered with reference to ufs file system but it can be used in Linux systems as

fsck -t ext2 /dev/sda3
fsck.ext2 /dev/sda3
fsck.ext4 /dev/sda3
fsck.ext3 /dev/sda3

it returns with any of the followig code

0 – No errors
1 – File system errors corrected
2 – System should be rebooted
4 – File system errors left uncorrected
8 – Operational error
16 – Usage or syntax error
32 – Fsck canceled by user request
128 – Shared library error

fsck checks the file systems defined in /etc/fstab in Linux and /etc/vfstab in Unix systems