UNIX file content display commands cat, more, less, Head, and tail

■ Cat command

Displays the file content.

Assume that the F. Java file exists. Each time you input a line, a blank line is displayed ,:

● Default options

:

●-A Option

Displays the file content, ^ I mark (Tab key), and $ mark (line break ). :

●-B Option

The text line number is displayed. Empty rows are not included. :

●-E Option

Show text lines and line feed $. :

●-E Option

The $ symbol is displayed at the end of each line. : Same as-e option.

●-N Option

Line numbers are displayed on each line, and empty rows are also included. :

●-T Option

Display the tab key and mark it as ^ I.

●-S option

When there is a blank space larger than two rows, only one row is displayed for compression.

Suppose f. Java is as follows:

The-s option is displayed as follows:

■ More command

Assume that the F. Java file exists and there is no blank line.

● Default options

:

●-Num Option

Specifies an integer, such as num = 2, indicating the number of lines of text displayed at one time on the current screen. For example, execute more-2 F. Java ,:

It can be seen that only two lines of text are displayed. Click the Space key to continue.

●-D option

When the file content cannot be displayed on a screen, the following button is displayed: Press space to continue, 'q' to quit. :

●-Num Option

● +/Option

You can enter a matched string after the slash (+/). If the specified file does not exist, a prompt is displayed. Otherwise, the row of the corresponding string is displayed.

The string out exists in the F. Java file. If you execute more +/out f. Java, the F. Java content is directly displayed.

If the astring does not exist in the F. Java file ,:

Click the Space key to display the content of the f. Java file.

■ Less command

The less command is similar to the more command, but the less command can be the same as the VI editor. For example, enter the following command:

Less hello. C f. Java

Enter two files to enter the mode:

The following line shows that the next file is F. java. You can directly type "N" to display the content of the f. Java file ,:

In this mode, enter the command: P to view the previous file hello. C.

For the less command, you can directly enter the man less command to view the help manual.

■ Head command

● Default options

If no option is specified, for example, if head f. Java is executed, all contents of the f. Java file are displayed.

●-N Option

Displays the first n rows of the specified file. N is an integer. :

The first two lines of the f. Java file are displayed.

In addition, the header information of multiple files can be displayed (specify the first n rows ),:

■ Tail command

● Default options

If no options are specified, for example, if tail F. Java is executed, all contents of the f. Java file are displayed.

●-N Option

The last n rows of the specified file are displayed. N is an integer. :

The last four lines of the f. Java file are displayed.

In addition, the tail information of multiple files can be displayed (the last n rows are specified ),: