diff Command JACARY RICHARDSON NHANTRUNG PHAN Unix/Linux Command: - PowerPoint PPT Presentation

diff Command JACARY RICHARDSON NHANTRUNG PHAN

Unix/Linux Command: diff  The diff utility is at its very base a data comparison tool  Generally, the diff command compares two files in the following format:  diff filename1 filename2  If you use a filename of just “ - ”, you can compare text from the standard input with a different file  diff is a line-oriented comparison tool and tries to find the smallest numbers of insertion and deletions to create one file from the other  Diff options begin with a “ - ” so you can’t use a file whose name starts with a “ - ”

diff options  -a: Treat all files as text files  -b: Ignore changes in amount of white space (such as spaces or tabs)  -B: Ignore changes in amount of blank or empty lines  -e: Create an editing script that contains a sequence of commands to change one file’s contents to another that can you used in the editing programs ed/ex  -i: Ignore difference in cases (upper and lower case characters are treated the same)  -y: Display output in two columns

Lines that aren’t changed aren’t • shown in diff In standard output a = add, c = • changed, and d = deleted Line numbers of the first file are • shown before a/c/d and line numbers of the second file are displayed after < is a deletion line showing that • the line is deleted in the second file > is an addition line that shows • the line is added in the second file

Works Cited  http://linux.about.com/library/cmd/blcmdl1_diff.htm  http://www.computerhope.com/unix/udiff.htm