删除文件第一行： sed '1d' filename
删除文件最后一列： awk '{print $NF}' filename
awk删除重复行的命令：awk '{if (!seen[$0]++) {print $0;}}' filename
比较文件的两种方法：
1）comm -3 --nocheck-order file1 file2
2) grep -v -f file1 file2 :输出file2中有file1中没有的行
当然还有diff file1 file2
贴一段昨天写的shell脚本~
#!/bin/bash
date_time=`date +'%H_%M_%S'`
yesterday=`date -d"-1 day" +'%Y_%m_%d'`
today=`date +'%Y_%m_%d'`
date_day_time=`date +'%Y_%m_%d_%H_%M_%S'` mkdir /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/same_similiar_log/$today # begin to get input files which haven't been deal with
today_input=/home/crawler/petabyte/crawllog/news_data/$today
yesterday_input=/home/crawler/petabyte/crawllog/news_data/$yesterday /opt/hadoop/program/bin/hadoop fs -ls $yesterday_input/ > /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/all_get
/opt/hadoop/program/bin/hadoop fs -ls $today_input/ >> /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/all_get sed '1d' /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/all_get > /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/all_get_without_first_line awk '{print $NF}' /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/all_get_without_first_line > /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/all_input #comm - --nocheck-order /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/all_input /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/input_done > /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/today_diff grep -v -f /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/input_done /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/all_input > /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/today_diff awk '{print $NF}' /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/today_diff > /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/today_new_input mv /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/all_input /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/input_done # begin to compute same_similary_news
inputfile1=""
while read line
do
inputfile1=$inputfile1,${line}
done < /home/spamdetect/changxiaojia/workspace/finance/same_similar_news_mining/mid_files/input_done
echo $inputfile1