介紹
build and execute command lines from standard input
用法
假設有個檔案結構如下 :
$ tree test
test
├── c1
│ ├── ii.del
│ └── pp.ext
├── c2
│ ├── gg.del
│ └── hh.ext
└── c3
├── c3-1
│ ├── qq.del
│ └── xx.ext
├── cc.ext
└── ff.del
4 directories, 8 files
如果我要刪除 test 下所有 *.del 的檔案
找出 *.del
$ find test -name "*.del"
test/c3/ff.del
test/c3/c3-1/qq.del
test/c2/gg.del
test/c1/ii.del
加上 xargs 指令, 可以一次幫你把找到的結果刪除
$ find test -name "*.del" | xargs rm
如果前面 find 那邊沒有任何結果輸出會出現錯誤訊息
rm: missing operand
Try 'rm --help' for more information.
可加上 --no-run-if-empty 來避免 :
$ find test -name "*.del" | xargs --no-run-if-empty rm
--no-run-if-empty or -r : If the standard input does not contain any nonblanks, do not run the command. Normally, the command is run once even if there is no input. This option is a GNU extension.
將筆對到的字串暫存成符號供取代使用, linux supports -i, mac supports -I
mac
redis-cli KEYS "user:???" | xargs -I@ redis-cli HSET @ field1 1
linux
redis-cli KEYS "user:???" | xargs -i@ redis-cli HSET i field1 1
Add file extension
$ tree .
.
├── cc
└── qq
$ ls | xargs -I file mv file file.txt && ls
cc.txt qq.txt
不用 xargs 且達到一樣效果 :
$ for i in `ls`;do mv $i ${i}.txt; done && ls
cc.txt qq.txt
- xargs :
- -I replace-str
-
Replace occurrences of replace-str in the initial-arguments with names read from standard input.
-
Also, unquoted blanks do not terminate input items; instead the separator is the newline
-
character. Implies -x and -L 1.
Change file extension
change xxx.thml -> xxx.txt
ls | grep html | sed 's/.html//g' | xargs -I file mv file.html file.txt
Add prefix
ls | xargs -I {FILE} mv {FILE} prefix_{FILE}
{FILE} 是自訂讓 xargs 辨識用的變數名稱
Example
將指到的檔都刪除
find -name "*.bak" | xargs rm
如果沒有找到也不要噴出錯誤訊息
find -name "*.bak" | xargs --no-run-if-empty rm
ref :
http://blog.yam.com/ddy1280/article/13941218