diff command in Linux with examples. diff stands for difference. This command is used to display the differences in the files by comparing the files line by line. Unlike its fellow members, cmp and comm, it tells us which lines in one file have is to be changed to make the two files identical.
What is use of diff command?
diff is a command-line utility that allows you to compare two files line by line. It can also compare the contents of directories. The diff command is most commonly used to create a patch containing the differences between one or more files that can be applied using the patch command.
How does diff command work in Unix?
On Unix-like operating systems, the diff command analyzes two files and prints the lines that are different. In essence, it outputs a set of instructions for how to change one file to make it identical to the second file.
What is the output of diff command in Unix?
The diff command is invoked from the command line, passing it the names of two files: diff original new . The output of the command represents the changes required to transform the original file into the new file. If original and new are directories, then diff will be run on each file that exists in both directories.
How do I diff files?
The following are examples of how to use the diff command:
- To compare two files, type the following: diff chap1.bak chap1. This displays the differences between the chap1. …
- To compare two files while ignoring differences in the amount of white space, type the following: diff -w prog.c.bak prog.c.
What is diff in coding?
Alternatively referred to as compare, diff is short for different or difference and describes a program’s ability to show the difference between two or more files. A diff is an invaluable tool in programming as it enables a developer to see what has changed in-between versions.
What is difference between comm and CMP command?
Different ways of comparing two files in Unix
#1) cmp: This command is used to compare two files character by character. Example: Add write permission for user, group and others for file1. #2) comm: This command is used to compare two sorted files.
What does 2 mean in Linux?
38. File descriptor 2 represents standard error. (other special file descriptors include 0 for standard input and 1 for standard output). 2> /dev/null means to redirect standard error to /dev/null . /dev/null is a special device that discards everything that is written to it.
How do you use cmp?
When cmp is used for comparison between two files, it reports the location of the first mismatch to the screen if difference is found and if no difference is found i.e the files compared are identical. cmp displays no message and simply returns the prompt if the the files compared are identical.
What does df command do in Linux?
df (abbreviation for disk free) is a standard Unix command used to display the amount of available disk space for file systems on which the invoking user has appropriate read access. df is typically implemented using the statfs or statvfs system calls.
How do you interpret differential output?
The diff command can display the output in several formats with the normal, context, and unified format being the most common ones. The output includes information about which lines in the files must be changed so that they become identical. If the files match, no output is produced.
What does git diff do?
git diff is a multi-use Git command that when executed runs a diff function on Git data sources. These data sources can be commits, branches, files and more. … The git diff command is often used along with git status and git log to analyze the current state of a Git repo.
What is File command in Linux?
file command is used to determine the type of a file. .file type may be of human-readable(e.g. ‘ASCII text’) or MIME type(e.g. ‘text/plain; charset=us-ascii’). … language test: This test search for particular strings which can appear anywhere in the first few blocks of a file.
How do I compare two files in Linux?
You can use diff tool in linux to compare two files. You can use –changed-group-format and –unchanged-group-format options to filter required data. Following three options can use to select the relevant group for each option: ‘%<' get lines from FILE1.