To some extent every file is a binary file. But some files are called text files or ascii files. These files are a collection of lines of printable characters.

Calling them text files is perhaps better than ASCII files, since other character sets are starting to be used. Unix does have a second meaning for "text" though. An executable file (which would be considered a binary file) cannot be deleted while it is running. You get a "text file busy" error message. This refers to the text segment of of program and has nothing to do with human readable text. See: finding out the pid for a busy text file.

Some programs process text files by reading a line at a time. This leads a concept of Max no. of characters in a line.

On Unix, a line to terminated by a newline character. On Windows and Dos, a line is terminated by a carriage return/line feed combination. The line feed and the newline are the same character. So the difference is the presense or absence of the carriage return character.

During an ftp file transfer, you can select "ASCII" mode. This tells ftp to convert the line formats as it moves bewteen two different OS's. If you transfer the file in binary mode, the conversion will not occur. In that case, you can see stuff like there was a strange character(^M) been added automatically in UNIX.

More threads on fixing text files:

Can we use sed for this?

windows file to unix :end line chararcter

Convert ASCII to BINARY

replacing \n by \r\n

We don't have threads telling how to fix a binary file transfered in ascii mode. That cannot be done.


Finally here is an interesting thread that deals with determining whether or not a file is a text file: How to determine if a file is ASCII?