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diff --git a/pkg/system/tail.x b/pkg/system/tail.x
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+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include	<error.h>
+
+# TAIL -- Print the tail (last few lines) of each of the named text files on the
+# standard output.  If more than one file is to be printed, a brief header is
+# printed for each file.
+# 
+# Params:
+# 	input_files		File matching template
+# 	nlines [h,12]		Number of lines at tail of file to be printed
+#
+# If NLINES is negative, its absolute value is the number of lines to skip at
+# head of file.
+
+procedure t_tail()
+
+char	fname[SZ_FNAME]
+bool	multiple_files
+int	nlines, list
+int	clpopni(), clplen(), clgfil(), clgeti()
+
+begin
+	list = clpopni ("input_files")
+	nlines = clgeti ("nlines")
+
+	multiple_files = (clplen (list) > 1)
+	
+	while (clgfil (list, fname, SZ_FNAME) != EOF)
+	    iferr (call print_tail (STDOUT, fname, nlines, multiple_files))
+		call erract (EA_WARN)
+
+	call clpcls (list)
+end
+
+
+# PRINT_TAIL -- Print the last few lines of a file on the output stream
+# given as the first argument, optionally plus a header.
+
+procedure print_tail (out, fname, nlines, print_file_name)
+
+char	fname[ARB]
+int	out, nlines
+bool	print_file_name
+
+pointer	sp, offsets, line
+int	in, linenum, index, noffsets, nlines_in_file
+int	open(), getline()
+long	note()
+errchk	open, getline, putline, note
+
+begin
+	if (nlines == 0)
+	    return
+	else
+	    noffsets = abs (nlines) + 1
+
+	call smark (sp)
+	call salloc (line, SZ_LINE, TY_CHAR)
+	call salloc (offsets, noffsets, TY_LONG)
+
+	# Open the file.
+	in = open (fname, READ_ONLY, TEXT_FILE)
+
+	if (print_file_name) {
+	    call fprintf (out, "\n\n===> %s <===\n")
+		call pargstr (fname)
+	}
+
+	# If nlines is negative, skip nlines lines at head of file and
+	# print rest of file.  If nlines is positive, print nlines lines
+	# at tail of file.
+
+	linenum = 0
+	repeat {
+	    linenum = linenum + 1
+	    if (nlines < 0 && linenum > -nlines)
+		break
+	    else if (nlines > 0) {
+		index = mod (linenum - 1, noffsets)
+		Meml[offsets+index] = note (in)
+	    }
+	} until (getline (in, Memc[line]) == EOF)
+
+	nlines_in_file = linenum - 1
+
+	# Seek back to offset of desired line, if not skipping head of file.
+	if (nlines > 0)
+	    if (nlines_in_file <= nlines)
+		call seek (in, BOFL)
+	    else {
+		index = mod (nlines_in_file - nlines, noffsets)
+		call seek (in, Meml[offsets+index])
+	    }
+
+	# If nlines is positive, print nlines lines, otherwise print rest
+	# of file.
+	linenum = 1
+	while ((linenum <= nlines || nlines < 0) &&
+	    (getline (in, Memc[line]) != EOF)) {
+		call putline (out, Memc[line])
+		linenum = linenum + 1
+	}
+
+	call sfree (sp)
+	call close (in)
+end