[Linux command] cat command option list [Must-see for beginners]

[Linux command] cat command option list [Must-see for beginners]

Summary Linux command list

What is the cat command?

This command outputs the file contents as standard. "cat" is an abbreviation for "concatenate". Since "concatenate" = "concatenate", it should be It may be more polite to say "concatenate file contents and output as standard" rather than "output file contents as standard".

How to use the cat command

/home/hoge

$cat target file

Cat command option list

-n option

Output with line numbers.

Without options

/home/hoge/test

$ cat test.txt
hoge
hogehoge

hogehogehoge



hogehogehogehoge

With the -n option, the output is as follows.

/home/hoge/test

$ cat -n test.txt
     1	hoge
     2	hogehoge
     3
     4	hogehogehoge
     5
     6
     7
     8	hogehogehogehoge
     9

-b option

Output with line numbers without blanks.

/home/hoge/test

$ cat -b test.txt
     1	hoge
     2	hogehoge

     3	hogehogehoge



     4	hogehogehogehoge

-s option

Output consecutive blank lines as one blank line

/home/hoge/test

$ cat -s test.txt
hoge
hogehoge

hogehogehoge

hogehogehogehoge

By the way, if you combine -s and -n ↓

/home/hoge/test

$ cat -ns test.txt
     1	hoge
     2	hogehoge
     3
     4	hogehogehoge
     5
     6	hogehogehogehoge
     7

-E option

Output with "" at the end of each line It's useful later when you replace "" with a comma to make an array.

/home/hoge/test

$ cat test.txt
hoge$
hogehoge$
$
hogehogehoge$
$
$
$
hogehogehogehoge$
$

-E option

Replace tab with "^ I" and output

In the following cases

/home/hoge/test

$ cat ex.txt
hoge
    hogehoge
        hogehogehoge

↓ It will be like this.

/home/hoge/test

$ cat ex.txt
hoge
^Ihogehoge
^I^Ihogehogehoge

Concatenated output of cat command

Output by concatenating multiple files. (Original cat)

/home/hoge/test

$ cat hoge.txt
hoge

$ cat hoge2.txt
hogehoge

$ cat hoge3.txt
hogehogehoge


$ cat hoge.txt hoge2.txt hoge3.txt
hoge
hogehoge
hogehogehoge

You can also create a new file that is concatenated.

/home/hoge/test

$ cat hoge.txt
hoge

$ cat hoge2.txt
hogehoge

$ cat hoge3.txt
hogehogehoge

#Create 3 files as superhoge
$ cat hoge.txt hoge2.txt hoge3.txt > superhoge

$ cat superhoge
hoge
hogehoge
hogehogehoge

List of options for other Linux commands

pwd, mkdir, cd , cat, cp, ls, touch, less, mv, rm, ssh, man, ** Adding at any time **

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