Recipe: head and tail -  Printing last/first 10 lines


$ cat file
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

Print first 10 lines
=======================

$ head file
1
2
3
4
5
6
7
8
9
10


Read data from stdin
=========================

$ cat file | head
1
2
3
4
5
6
7
8
9
10

Specify number of first lines to be printed
==============================================

$ head -n 4 file
1 
2
3
4

Print all lines excluding last N lines
=======================================

$ head -n -N file

$ seq 100 | head -n 5

1
2
3
4
5

$ tail file
6
7
8
9
10
11
12
13
14
15

$ cat file | tail
6
7
8
9
10
11
12
13
14
15

$ tail -n 5 file
11
12
13
14
15

$ seq 10 | tail -n +6 
6
7
8
9
10

Follow the growth of growing files
======================================

$ tail -f growing_file

$i dmesg |tail -f
[ 8521.838740] ata1: exception Emask 0x10 SAct 0x0 SErr 0x50000 action 0xe frozen
[ 8521.838746] ata1: irq_stat 0x00400000, PHY RDY changed
[ 8521.838751] ata1: SError: { PHYRdyChg CommWake }
[ 8521.838759] ata1: hard resetting link
[ 8522.552189] ata2: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[ 8522.557500] ata2.00: configured for UDMA/100
[ 8522.558602] ata2: EH complete
[ 8522.560144] ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[ 8522.588950] ata1.00: configured for UDMA/133
[ 8522.588960] ata1: EH complete


Terminate after a given process ID dies.
===========================================

$ PID=$(pidof Foo)
$ tail -f file –pid PID