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35 .\" @(#)tail.1 8.1 (Berkeley) 6/6/93
43 .Nd display the last part of a file
49 .Fl b Ar number | Fl c Ar number | Fl n Ar number
55 utility displays the contents of
57 or, by default, its standard input, to the standard output.
59 The display begins at a byte, line or 512-byte block location in the
61 Numbers having a leading plus
63 sign are relative to the beginning
64 of the input, for example,
66 starts the display at the second
68 Numbers having a leading minus
70 sign or no explicit sign are
71 relative to the end of the input, for example,
73 displays the last two lines of the input.
74 The default starting location is
76 or the last 10 lines of the input.
78 The options are as follows:
79 .Bl -tag -width indent
93 to not stop when end of file is reached, but rather to wait for additional
94 data to be appended to the input.
97 option is ignored if the standard input is a pipe, but not if it is a FIFO.
105 will also check to see if the file being followed has been renamed or rotated.
106 The file is closed and reopened when
108 detects that the filename being read from has a new inode number.
110 If the file being followed does not (yet) exist or if it is removed, tail
111 will keep looking and will display the file from the beginning if and when
116 option is the same as the
118 option if reading from standard input rather than a file.
124 Suppresses printing of headers when multiple files are being examined.
128 option causes the input to be displayed in reverse order, by line.
129 Additionally, this option changes the meaning of the
136 option is specified, these options specify the number of bytes, lines
137 or 512-byte blocks to display, instead of the bytes, lines or blocks
138 from the beginning or end of the input from which to begin the display.
141 option is to display all of the input.
144 If more than a single file is specified, each file is preceded by a
145 header consisting of the string
146 .Dq Li "==> " Ns Ar XXX Ns Li " <=="
149 is the name of the file unless
161 utility is expected to be a superset of the
169 options are extensions to that standard.
171 The historic command line syntax of
173 is supported by this implementation.
174 The only difference between this implementation and historic versions
177 once the command line syntax translation has been done, is that the
186 displays the last 4 characters of the last line
187 of the input, while the historic tail (using the historic syntax
191 option and display the last 4 lines of the input.
195 command appeared in PWB UNIX.