Cat command is used to concatenate files and to view the contents of files on the standard output in Linux. The following 15 examples can help us understand how to use Linux cat command.
Cat Options
-A, --show-all equivalent to -vET
-b, --number-nonblank number nonempty output lines, overrides -n
-e equivalent to -vE
-E, --show-ends display $ at end of each line
-n, --number number all output lines
-s, --squeeze-blank suppress repeated empty output lines
-t equivalent to -vT
-T, --show-tabs display TAB characters as ^I
-u (ignored)
-v, --show-nonprinting use ^ and M- notation, except for LFD and TAB
Display a File Using cat
The cat command displays a file to the screen.
cat filenameCat Command with More & Less Options
cat filename|morecat filename|lessShow Line Numbers using Cat
If there are lines with no characters at all they won't be numbered. For all the non-empty lines in a file use the following command:
cat -b filenameTo show numbers for all the lines regardless as to whether they are blank, type the following command:
cat -n filenameDisplay non-printing characters using Cat
cat -e filenameReducing Blank Lines with Cat
When we show the contents of a file using the cat command we probably don't want to see when there are loads of consecutive blank lines. Use the -s switch to condense all blank lines into a single blank line:
cat -s filenameCopy the contents of one file to another
cat filename > filename-newAppending the contents of one file to another
cat filename >> filename-newView the contents of many files with Cat
cat filename1 filename2 filename3Redirecting the output of multiple files into a single file
cat filename1 filename2 filename3 > filename-newSorting Contents of Multiple Files in a Single File
cat filename1 filename2 filename3|sort > filename-new