1、测试数据

root@PC1:/home/test2# ls
test.txt
root@PC1:/home/test2# cat test.txt   ## 测试数据
a 3 5 d
s g e z
c g w k
z c m d

 

2、xargs实现（数据大时不适用）

root@PC1:/home/test2# ls
test.txt
root@PC1:/home/test2# cat test.txt
a 3 5 d
s g e z
c g w k
z c m d
root@PC1:/home/test2# cat test.txt | xargs
a 3 5 d s g e z c g w k z c m d

 

3、tr + sed实现

root@PC1:/home/test2# ls
test.txt
root@PC1:/home/test2# cat test.txt
a 3 5 d
s g e z
c g w k
z c m d
root@PC1:/home/test2# cat test.txt | tr "\n" " " | sed 's/$/\n/'
a 3 5 d s g e z c g w k z c m d

 

4、awk实现

root@PC1:/home/test2# ls
test.txt
root@PC1:/home/test2# cat test.txt
a 3 5 d
s g e z
c g w k
z c m d
root@PC1:/home/test2# awk 'BEGIN{RS = EOF}{gsub("\n"," ");print}' test.txt
a 3 5 d s g e z c g w k z c m d

 

5、sed实现（速度慢）

root@PC1:/home/test2# ls
test.txt
root@PC1:/home/test2# cat test.txt
a 3 5 d
s g e z
c g w k
z c m d
root@PC1:/home/test2# sed ':a; N; s/\n/ /; ta' test.txt
a 3 5 d s g e z c g w k z c m d

 

6、awk实现

root@PC1:/home/test2# ls
test.txt
root@PC1:/home/test2# cat test.txt
a 3 5 d
s g e z
c g w k
z c m d
root@PC1:/home/test2# awk '{printf("%s ", $0)}END{printf("\n")}' test.txt
a 3 5 d s g e z c g w k z c m d