CODEWITHSUNDEEP
linuxshellunix
Rebooting
Rebooting

Reputation: 2938

unix- show the second line of the file

this command displays the second line of the file :

cat myfile | head -2 | tail -1

My file contains the following data : 

hello
mark
this is the head line
this is the first line 
this is the second line 
this is the last line

the command above prints the data as: mark

But i am unable to understand this because, head -2 is used to print the first two lines and tail -1 prints the last line but how come 2nd line is printed!!???

Upvotes: 41

Views: 120549

Answers (4)

Du-Lacoste
Du-Lacoste

Reputation: 12767

You could use sed command. Following are ways you could print the line number, you may select as per your task.

sed -n '2p' filename #get the 2nd line and prints the value (p stands for print)

sed -n '1,2p' filename #get the 1 to 2nd line and prints the values

sed -n '1p;2p;' filename #get the 1st and 2nd line values only

Upvotes: 5

Arun Taylor
Arun Taylor

Reputation: 1572

If you break up operations into separate commands, it will become obvious why it works the way it works.

head -2 creates a file of two lines.

linux> head -2 /tmp/x > /tmp/xx
linux> cat /tmp/xx  
hello
mark

tail -1 prints out the last line in the file.

linux> tail -1 /tmp/xx
mark

Upvotes: 2

paulsm4
paulsm4

Reputation: 121649

You can also use "sed" or "awk" to print a specific line:

EXAMPLE:

sed -n '2p' myfile

PS: As to "what's wrong with my 'head|tail'" command - shelltel is correct.

Upvotes: 47

perreal
perreal

Reputation: 97948

tail displays the last line of the head output and the last line of the head output is the second line of the file.

Output of head (input to tail):

hello
mark

Output of tail:

mark

Upvotes: 22

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