98 lines
2.9 KiB
Python
Executable File
98 lines
2.9 KiB
Python
Executable File
#!/usr/bin/env python
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#
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# Copyright 2015 Ville Rantanen
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#
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# This program is free software: you can redistribute it and/or modify it
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# under the terms of the GNU Lesser General Public License as published
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# by the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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#
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'''simple tail for tsv/csv files.'''
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__author__ = "Ville Rantanen <ville.q.rantanen@gmail.com>"
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__version__ = "0.1"
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import sys,os,argparse
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from argparse import ArgumentParser
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def setup_options():
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''' Create command line options '''
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usage='''
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simple implementation of tail, keeping the header row
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'''
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parser=ArgumentParser(description=usage,
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formatter_class=argparse.RawDescriptionHelpFormatter,
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epilog="\n".join(["Version: "+__version__,__author__]))
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common_group=parser.add_argument_group('common', 'Common options')
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common_group.add_argument("-v","--version",action="version",version=__version__)
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common_group.add_argument("-n",type=str,dest="lines",default=False,
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help="Lines to show from end of file. +K to start output from the Kth. Default: 10")
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parser.add_argument("file",type=str, nargs='*',
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help="File(s) to be headed")
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opts=parser.parse_args()
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if not opts.lines:
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try:
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int(opts.file[0])
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opts.lines=opts.file.pop(0)
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except:
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pass
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if not opts.lines:
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opts.lines="10"
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if opts.lines.startswith("+"):
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opts.lines=-int(opts.lines)
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else:
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opts.lines=int(opts.lines)
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return opts
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def tail(fileob,opts):
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header=fileob.readline()
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sys.stdout.write(header)
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if opts.lines>=0:
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tail_ordinary(fileob, opts.lines)
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else:
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tail_allbutfirst(fileob, -opts.lines)
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def tail_allbutfirst(fileob, lines):
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for i,row in enumerate(fileob):
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if i<lines-1:
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continue
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sys.stdout.write(row)
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def tail_ordinary(fileob, lines):
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buf=[]
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for row in fileob:
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buf.append(row)
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if len(buf)>lines:
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buf.pop(0)
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[sys.stdout.write(l) for l in buf]
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def main():
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opts=setup_options()
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try:
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if (not sys.stdin.isatty()):
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tail(sys.stdin, opts)
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for fi in opts.file:
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tail(open(fi,'r'), opts)
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except IOError as (n,e):
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if n==32:
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pass
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else:
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import traceback
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print traceback.format_exc()
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if __name__ == "__main__":
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main()
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