Linux System - Table 12 > Packages - Table 12 > ed

ed is a line-oriented text editor. It is used to create, display, modify and otherwise manipulate text files. red is a restricted ed: it can only edit files in the current directory and cannot execute shell commands. If invoked with a file argument, then a copy of file is read into the editor's buffer. Changes are made to this copy and not directly to file itself. Upon quitting ed, any changes not explicitly saved with a `w' command are lost.