升级显卡驱动后无法进入图形界面，并且在命令行界面中也常出现各种错误
我在桌面上有一个in文件夹和一个out文件夹，in文件夹中有十个不同的文件，如a.fas, b.fas, c.fas .......， 每个文件内容如下所示（每个文件有多条序列，每条序列名都在>号后面，序列名要保留和原来一样）！我想将每条序列的最后面20个碱基除去，然后用相同的文件名字保存在out文件夹中，我应该如何写脚本！
>Myotis ricketti
ATGGATCATGCTGAAGAAACTGAAATCCTTGCAGCGGCCCAGAAGTACTATGTGGACAGG
CCTATCTTCAGTCACCTGGCCCTCCAGGAAATACTGCACACGAAGGACAAGATTCCGGAT
TCCATTGGGGATAAGCTAAAACAGGCATTCACATGTACTCCGAAGAAAATAAGAAATATC
ATTTATATGTTCTTACCCATAACTAAGTGGTTGCCAGCATACAAATTCAAGGAGTATGTG
TTGGGTGACTTGGTCTCAGGCATTAGCACAGGGGTGCTTCAGCTTCCTCAAGGCTTAGCC
TTCGCAATGTTGGCAGCTGTGCCTCCGGTGTTCGGCCTGTACTCTTCGTTTTACCCTGTT
ATCATGTATTGTTTTTTTGGAACCTCCAGACACATATCCATAGGTCCGTTTGCTGTAATT
AGCCTGATG
>Rhinopoma hardwickii
ATGGATCATGCTGAAGAAAATGAAATCCTTGCAGCAACCCAGAGGTACTATGTGGAAAGG
CCTATCTTTAGTCATCCCATCCTCCAGGAAAGACTGCACCAGAAGGACAAGATTTCGGAT
TCCATTGGGGATAAGCTGAAACAGGCATTCACATGTACTCCTAAGAAAATAAGAAATATC
ATTTATATGTTCTTACCCATAACTGAGTGGCTGCCAGCATACAAATTCAAGGAGTATGTG
TTGGGTGACTTGGTCTCAGGCATAAGCACAGGGGTGCTTCAGCTTCCTCAAGGTTTAGCC
TTTGCAATGTTGGCAGCTGTGCCTCCGGTGTTTGGCCTGTACTCTTCGTTTTACCCTGTT
ATCATGTATTGCTTTTTTGGAACCTCCAAACACATATCCATAGGTCCATTTGCTGTTATT
AGCCTGATG
>Murina leucogaster
ATGGATCATGCTGAAGAAACTGAAATCCTTGCAGCGGCCCAGAAGTACTATGTGGACAGG
CCTATCTTTAGTCACCTGGCCCTCCAGGAAATACTGCACACGAAGGACAAGATTCCGGAT
TCCATTGGGGATAAGCTAAAACAGGCGTTCACATGTACTCCTAAGAAAATAAGAAATATC
ATTTATATGTTCTTACCCATAACTGAGTGGTTGCCAGCATACAAATTCAAGGAGTATGTG
TTGGGTGACTTGGTCTCAGGCATTAGCACAGGGGTGCTTCAGCTTCCTCAAGGCTTAGCC
TTCGCAATGCTGGCAGCTGTGCCTCCGGTGTTCGGCCTGTACTCCTCGTTTTACCCTGTT
ATCATGTATTGTTTTTTTGGAACCTCCAAACACATATCCATAGGTCCGTTTGCTGTAATT
AGCCTGATG
>Megaderma lyra
ATGGATCATGCTGAAGAAACTGAAATCCTTGCAGCAACCCAGAAGTACTATGTGGAAAGG
CCTATCTTTAGTCATTCAGTCCTCCAGGAAAGACTGCACAAGAAGGACAAGATTTCAGAG
TCCATTGGGGATAAGCTGAAACAGGCATTCACATGTACTCCTAAGAAAATAAGAAATATC
ATTTATATGTTCCTACCCATAACTAAGTGGTTGCCAGCATACAATTTCAAGGAATATGTG
TTGGGTGACTTGGTCTCAGGCATAAGCACAGGAGTGCTTCAGCTTCCTCAAGGTTTAGCC
TTTGCAATGTTGGCAGCTGTGCCACCAGTGTTTGGCCTGTACTCTTCGTTTTACCCTGTT
ATCATGTATTGCTTTTTTGGAACCTCCAGACATATATCCATAGGTCCATTTGCTGTTATT
AGCCTGATG
>Myotis ricketti
ATGGATCATGCTGAAGAAACTGAAATCCTTGCAGCGGCCCAGAAGTACTATGTGGACAGG
CCTATCTTCAGTCACCTGGCCCTCCAGGAAATACTGCACACGAAGGACAAGATTCCGGAT
TCCATTGGGGATAAGCTAAAACAGGCATTCACATGTACTCCGAAGAAAATAAGAAATATC
ATTTATATGTTCTTACCCATAACTAAGTGGTTGCCAGCATACAAATTCAAGGAGTATGTG
TTGGGTGACTTGGTCTCAGGCATTAGCACAGGGGTGCTTCAGCTTCCTCAAGGCTTAGCC
TTCGCAATGTTGGCAGCTGTGCCTCCGGTGTTCGGCCTGTACTCTTCGTTTTACCCTGTT
ATCATGTATTGTTTTTTTGGAACCTCCAGACACATATCCATAGGTCCGTTTGCTGTAATT
AGCCTGATG
>Rhinopoma hardwickii
ATGGATCATGCTGAAGAAAATGAAATCCTTGCAGCAACCCAGAGGTACTATGTGGAAAGG
CCTATCTTTAGTCATCCCATCCTCCAGGAAAGACTGCACCAGAAGGACAAGATTTCGGAT
TCCATTGGGGATAAGCTGAAACAGGCATTCACATGTACTCCTAAGAAAATAAGAAATATC
ATTTATATGTTCTTACCCATAACTGAGTGGCTGCCAGCATACAAATTCAAGGAGTATGTG
TTGGGTGACTTGGTCTCAGGCATAAGCACAGGGGTGCTTCAGCTTCCTCAAGGTTTAGCC
TTTGCAATGTTGGCAGCTGTGCCTCCGGTGTTTGGCCTGTACTCTTCGTTTTACCCTGTT
ATCATGTATTGCTTTTTTGGAACCTCCAAACACATATCCATAGGTCCATTTGCTGTTATT
AGCCTGATG
>Murina leucogaster
ATGGATCATGCTGAAGAAACTGAAATCCTTGCAGCGGCCCAGAAGTACTATGTGGACAGG
CCTATCTTTAGTCACCTGGCCCTCCAGGAAATACTGCACACGAAGGACAAGATTCCGGAT
TCCATTGGGGATAAGCTAAAACAGGCGTTCACATGTACTCCTAAGAAAATAAGAAATATC
ATTTATATGTTCTTACCCATAACTGAGTGGTTGCCAGCATACAAATTCAAGGAGTATGTG
TTGGGTGACTTGGTCTCAGGCATTAGCACAGGGGTGCTTCAGCTTCCTCAAGGCTTAGCC
TTCGCAATGCTGGCAGCTGTGCCTCCGGTGTTCGGCCTGTACTCCTCGTTTTACCCTGTT
ATCATGTATTGTTTTTTTGGAACCTCCAAACACATATCCATAGGTCCGTTTGCTGTAATT
AGCCTGATG
>Megaderma lyra
ATGGATCATGCTGAAGAAACTGAAATCCTTGCAGCAACCCAGAAGTACTATGTGGAAAGG
CCTATCTTTAGTCATTCAGTCCTCCAGGAAAGACTGCACAAGAAGGACAAGATTTCAGAG
TCCATTGGGGATAAGCTGAAACAGGCATTCACATGTACTCCTAAGAAAATAAGAAATATC
ATTTATATGTTCCTACCCATAACTAAGTGGTTGCCAGCATACAATTTCAAGGAATATGTG
TTGGGTGACTTGGTCTCAGGCATAAGCACAGGAGTGCTTCAGCTTCCTCAAGGTTTAGCC
TTTGCAATGTTGGCAGCTGTGCCACCAGTGTTTGGCCTGTACTCTTCGTTTTACCCTGTT
ATCATGTATTGCTTTTTTGGAACCTCCAGACATATATCCATAGGTCCATTTGCTGTTATT
AGCCTGATG
作者: shuifeng1988 发布时间: 2011-04-19
我的操作系统是ubuntu 10.10
作者: shuifeng1988 发布时间: 2011-04-19
我只擅长C
作者: goldfox_79 发布时间: 2011-04-19
如果有人写出来借我参考一下。。。 
作者: HelloAndroid 发布时间: 2011-04-19