tr使用

tr用来从标准输入中通过替换或删除操作进行字符转换。tr主要用于删除文件中控制字符或进行字符转换。

tr中特定控制字符的不同表达方式

速记符　　   　　 含义                       八进制方式

\a　　　　　　　Ctrl-G铃声                \007　

\b                       Ctrl-H退格符             \010

\f                       Ctrl-L 走行换页          \014 

\n                      Ctrl-J 新行                 \012

\r                       Ctrl-M 回车               \015

\t                       Ctrl-I tab键               \011

\v                      Ctrl-X                       \030

$cat oops.txt

And the cowwwws went homeeeeeee
Or did they

删除重复字母

$tr -s "[a-z]"< oops.txt

And the cows went home
Or did they

设有plane.txt

$cat plane.txt

987932 Spitfire


190992 Lancaster

238991 Typhoon

用-s删除空行

$tr -s "[\012]" < plane.txt或 $tr -s "[\n]" < plane.txt

987932 Spitfire
190992 Lancaster
238991 Typhoon

大写到小写

$echo "May Day, May Day, Going Down.." | tr "[a-z]" "[A-Z]"

或$echo "May Day, May Day, Going Down.." | tr "[:lower:]" "[:upper:]"

$ cat diary.txt

monday 10:50
Tuesday 15:30
wednesday 15:30
thurday 10:30
Friday 09:20

删除后面的时刻，可用

$ tr -cs "[a-z][A-Z]" "[\012*]" < diary.txt

monday
Tuesday
wednesday
thurday
Friday