linux uniq 命令介紹

轉載地址：http://blog.csdn.net/zzxian/article/details/7200046

uniq [選項] 檔案

說明：這個命令讀取輸入檔案，並比較相鄰的行。在正常情況下，第二個及以後更多個重複行將被刪去，行比較是根據所用字元集的排序序列進行的。該命令加工後的結果寫到輸出檔案中。輸入檔案和輸出檔案必須不同。如果輸入檔案用“- ”表示，則從標準輸入讀取。

該命令各選項含義如下：、

– c 顯示輸出中，在每行行首加上本行在檔案中出現的次數。它可取代- u和- d選項。

– d 只顯示重複行。

– u 只顯示檔案中不重複的各行。

– n 前n個欄位與每個欄位前的空白一起被忽略。一個欄位是一個非空格、非定位字元的字串，彼此由定位字元和空格隔開(欄位從0開始編號)。

+n 前n個字元被忽略，之前的字元被跳過(字元從0開始編號)。

– f n 與- n相同，這裡n是欄位數。

– s n 與+n相同，這裡n是字元數。

接下來通過實踐執行個體說明：

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[root@stu100 ~]# cat testboy took bat homeboy took bat homegirl took bat homeboy took bat homeboy took bat homedog brought hat homedog brought hat homedog brought hat home

看test檔案的內容

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[root@stu100 ~]# uniq testboy took bat homegirl took bat homeboy took bat homedog brought hat home

uniq命令不加任何參數，僅顯示連續重複的行一次

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[root@stu100 ~]# uniq -c test2 boy took bat home1 girl took bat home2 boy took bat home3 dog brought hat home1

-c 參數顯示檔案中每行連續出現的次數。

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[root@stu100 ~]# cat test |sort | uniq -c14 boy took bat home3 dog brought hat home1 girl took bat home

排序後再顯示

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[root@stu100 ~]# uniq -d testboy took bat homeboy took bat homedog brought hat home

-d選項僅顯示檔案中連續重複出現的行。

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[root@stu100 ~]# uniq -u testgirl took bat home

-u選項顯示檔案中沒有連續出現的行。

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[root@stu100 ~]# uniq -f 2 -s 2 testboy took bat home

忽略每行的前2個欄位，忽略第二 個空白字元和第三個欄位的首字元，結果at home

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[root@stu100 ~]# uniq -f 1 testboy took bat homedog brought hat home

忽 略每行的第一個欄位，這樣boy ，girl開頭的行看起來是連續重複的行。

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[root@stu100 ~]# uniq -D testboy took bat homeboy took bat homeboy took bat homeboy took bat homedog brought hat homedog brought hat homedog brought hat home

顯示所有重複的行，每個重複的行都顯示