If we want to print out text in Linux system, we can use vi
/vim
to edit the text file.
But today if we just only want to check the file content, and don't need to change any content, we can use other commands to print out the file content.
Today, I want to record cat
, head
, tail
commands.
cat
cat
is a common Linux command, it can print out all content of file. For example, I want to check a file named wiki_rainbow.txt file:
cat wiki_rainbow
Output:
In addition to printing directly, the cat
command also has the following parameters that can be set:
- -n: Number of rows (starting from 1)
- -b: Blank lines are not numbered
- -s: Reduce consecutive blank lines to a single blank line
head
However, since cat
just can print out the entire file content, we can use head
to print out the beginning of the file when the content is too large or we only need part of the content.
There are two main display modes for head
:
- -c: Decide the number of characters to be printed
- -n: Determine the number of lines to be printed
for example:
head -n 5 wiki_rainbow.txt
Output:
As you can see, compared with just now, we only printed the first five lines.
tail
The tail
and head
commands are like instructions with opposite functions: head mainly prints the beginning, and tail prints the end.
Like head
, tail
also has the following parameters:
- -c: Decide the number of characters to be printed
- -n: Determine the number of lines to be printed
tail -n 4 wiki_rainbow.txt
Output:
It seems that the newline symbol "\n" is used to determine the number of lines.
References
- https://www.tecmint.com/view-contents-of-file-in-linux/
- https://2buntu.com/articles/1491/viewing-text-files-on-linux-cat-head-tail-more-and-less/