NAME

tail − deliver the last part of a file

SYNOPSIS

­tail [ +-number[lbc][rf] ] [ ­file ]

­tail [ ­-fr ] [ ­-n ­nlines ] [ ­-c ­nbytes ] [ ­file ]

DESCRIPTION

­Tail copies the named file to the standard output beginning at a designated place.  If no file is named, the standard input is copied. 

Copying begins at position +number measured from the beginning, or -number from the end of the input.  ­Number is counted in lines, 1K blocks or bytes, according to the appended flag l, b, or c.  Default is ­-10l (ten ell). 

The further flag ­r causes tail to print lines from the end of the file in reverse order; ­f (follow) causes tail, after printing to the end, to keep watch and print further data as it appears.

The second syntax is that promulgated by POSIX, where the ­numbers rather than the options are signed. 

EXAMPLES

­tail file
Print the last 10 lines of a file.

­tail +0f file
Print a file, and continue to watch data accumulate as it grows.

­sed 10q file
Print the first 10 lines of a file.

SOURCE

­/sys/src/cmd/tail.c

BUGS

Tails relative to the end of the file are treasured up in a buffer, and thus are limited in length. 

According to custom, option +number counts lines from 1, and counts blocks and bytes from 0. 

­Tail is ignorant of UTF. 

Plan 9  —  April 17, 2005