Shell学习——终端打印

Posted 2021-01-04 pigwan7

1、echo
1.1、默认情况下，echo在每次调用后会添加一个换行符
1.2、待打印的内容，可以用单引号、双引号或者直接打印，不同的方式，有各自的限制
1.2.1、使用不带引号的echo时，没法打印分好(;)，因为分号在Bash shell中用为命令界定符
[[email protected] ~]# echo hello world;
hello world
[[email protected] ~]# echo ‘hello world;‘
hello world;
[[email protected] ~]#
1.2.2、特殊字符在使用双引号打印时，需要加上转义字符
[[email protected] ~]# echo hello world !
hello world !
[[email protected] ~]# echo ‘hello world !‘
hello world !
[[email protected] ~]# echo "hello world !"
echo "hello world ","logger":"me.ele.acct.comm.biz.aop.MethodInvokeSection","sdatetime":"2018-08-17 14:07:53.075","datetime":"1534486073076","docker_pid":"22720","host":"xg-mesos-895","subappid":"","app_id":"me.ele.acct.server","seq":"153448607307611392
>
> ^C
[[email protected] ~]#
1.2.3、变量替换在单引号中无效
[[email protected] ~]# name=jack
[ro[email protected] ~]# echo $name
jack
[[email protected] ~]# echo "$name"
jack
[[email protected] ~]# echo ‘$name‘
$name
1.3、-n选项忽略结尾换行符
[[email protected] ~]# echo -n hello world
hello world[[email protected] ~]#
1.4、-e选项打印转义字符
[[email protected] ~]# echo -e "1 2 3"
1 2 3
[[email protected] ~]#
2、printf
2.1、printf使用引用文本或由空格分隔的参数，printf不会自动添加换行符，需要手动添加
[[email protected] shell]$ cat printf.sh
#!/bin/bash
#file:printf.sh

printf "%-5s %-10s %-4s " No Name Mark
printf "%-5s %-10s %-4.2f " 1 Jack 80.3456
printf "%-5s %-10s %-4.2f " 2 Jeff 77.56
[[email protected] shell]$ ./printf.sh
No Name Mark
1 Jack 80.35
2 Jeff 77.56
[[email protected] shell]$
%s %c %d和%f都是格式替换符，对应的参数置于带引号的格式字符串之后
-标识左对齐，默认是右对齐