Linux Shell - `echo` 命令输出格式

1. `echo` - display a line of text

Echo the STRING(s) to standard output.

echo [ˈekəʊ]：n. 回响，回声，回音，映现 v. 回响，回荡，发出回声，产生回响

1.1 User Commands

(base) yongqiang@yongqiang:~$ man echo

1.2 内容输出后换行 (自带换行符)

输出内容，然后输出换行符号。

(base) yongqiang@yongqiang:~$ echo "yongqiang"
yongqiang
(base) yongqiang@yongqiang:~$ echo yongqiang
yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo "Yongqiang Cheng"
Yongqiang Cheng
(base) yongqiang@yongqiang:~$ echo Yongqiang Cheng
Yongqiang Cheng
(base) yongqiang@yongqiang:~$

1.3 `-n` - do not output the trailing newline (取消换行符)

取消输出后行末的换行符号，内容输出后不换行。

trail [treɪl]：v. 跟踪，追踪，拖，磨蹭 n. 小径，路径，踪迹，足迹

(base) yongqiang@yongqiang:~$ echo "Yongqiang Cheng"
Yongqiang Cheng
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -n "Yongqiang Cheng"
Yongqiang Cheng(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$

如果加入 -n 选项，则在输出内容结束后，不会换行，直接显示新行的提示符。

(base) yongqiang@yongqiang:~$ echo Yongqiang Cheng
Yongqiang Cheng
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo Yongqiang; echo Cheng
Yongqiang
Cheng
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -n Yongqiang; echo Cheng
YongqiangCheng
(base) yongqiang@yongqiang:~$

加分号表示一条语句的完结。

1.4 `-e` - enable interpretation of backslash escapes (支持反斜线控制的字符转换)

检索语句中的转义符并执行，需要使用双引号 " "。

If -e is in effect, the following sequences are recognized:

\\     backslash - 输出 \
\a     alert (BEL) - 输出警告音
\b     backspace - 退格键，删除左边一个字符
\c     produce no further output - 取消输出行末的换行符，和 -n 选项一致
\e     escape - Esc 键
\f     form feed - 换页符
\n     new line - 换行符
\r     carriage return - 回车键
\t     horizontal tab - 水平制表符
\v     vertical tab - 垂直制表符
\0NNN  byte with octal value NNN (1 to 3 digits) - 按照八进制 ASCII 码表输出字符，其中 0 为数字 0，NNN 是三位八进制数
\xHH   byte with hexadecimal value HH (1 to 2 digits) - 按照十六进制 ASCII 码表输出字符，其中 hh 是两位十六进制数

carriage [ˈkærɪdʒ]：n. 运输，运费，举止，仪态

(base) yongqiang@yongqiang:~$ echo -e "\\"
\
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\a"(base) yongqiang@yongqiang:~$

\b 删除左边一个字符。

(base) yongqiang@yongqiang:~$ echo -e "yong\bqiang"
yonqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "yongqiang\b"
yongqiang
(base) yongqiang@yongqiang:~$

输出内容结束后，不会换行，且 \c 之后的内容不输出。

(base) yongqiang@yongqiang:~$ echo -e "yongqiang"
yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "yongqiang\c"
yongqiang(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "yong\cqiang"
yong(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$

\t 水平制表符，Tab 键。

(base) yongqiang@yongqiang:~$ echo -e "Aaa\tBbb\tCcc"
Aaa     Bbb     Ccc
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "Aaa\tBbb\tCcc\nDdd\tEee\tFff"
Aaa     Bbb     Ccc
Ddd     Eee     Fff
(base) yongqiang@yongqiang:~$

输入八进制，打印对应的 ASCII 码。65 = \0101 = ‘A’
输入十六进制，打印对应的 ASCII 码。65 = \x41 = ‘A’

(base) yongqiang@yongqiang:~$ echo -e "\0101\t\0102\t\0103\n\0104\t\0105\t\0106"
A       B       C
D       E       F
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\x41\t\x42\t\x43\n\x44\t\x45\t\x46"
A       B       C
D       E       F
(base) yongqiang@yongqiang:~$

\n 换行符

(base) yongqiang@yongqiang:~$ echo -e "yong\nqiang"
yong
qiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "yongqiang\n"
yongqiang(base) yongqiang@yongqiang:~$

\f 换页符

(base) yongqiang@yongqiang:~$ echo -e "yong\fqiang"
yong
qiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "yongqiang\f"
yongqiang(base) yongqiang@yongqiang:~$

\r 光标回到行首，后面输出的内容会覆盖之前的输出，可用于制作进度条。

(base) yongqiang@yongqiang:~$ echo -e "yong\rqiang"
qiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "yongqiang\rcheng"
chengiang
(base) yongqiang@yongqiang:~$

\v 垂直制表符

(base) yongqiang@yongqiang:~$ echo -e "yong\vqiang\vcheng"
yongqiangcheng
(base) yongqiang@yongqiang:~$

1.5 设置打印字体颜色

\e[ 是标准格式，代表颜色输出开始。
\e[0m 是标准格式，代表颜色输出结束。

字体颜色：30m=黑色，31m=红色，32m=绿色，33m=黄色，34m=蓝色，35m=洋红，36m=青色，37m=白色。

(base) yongqiang@yongqiang:~$ echo -e "\e[30m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[31m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[32m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[33m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[34m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[35m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[36m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[37m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$

字体颜色：1;30m=亮黑色，1;31m=亮红色，1;32m=亮绿色，1;33m=亮黄色，1;34m=亮蓝色，1;35m=亮洋红，1;36m=亮青色，1;37m=亮白色。

(base) yongqiang@yongqiang:~$ echo -e "\e[1;30m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[1;31m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[1;32m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[1;33m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[1;34m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[1;35m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[1;36m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[1;37m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$

1.6 设置打印字体背景颜色

\e[ 是标准格式，代表颜色输出开始。
\e[0m 是标准格式，代表颜色输出结束。
背景颜色：40m=黑色，41m=红色，42m=绿色，43m=黄色，44m=蓝色，45m=洋红，46m=青色，47m=白色。

(base) yongqiang@yongqiang:~$ echo -e "\e[40m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[41m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[42m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[43m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[44m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[45m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[46m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[47m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$

(base) yongqiang@yongqiang:~$ echo -e "\e[1;40m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[1;41m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[1;42m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[1;43m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[1;44m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[1;45m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[1;46m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\e[1;47m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$

1.7 打印设置

\033 和 \e 效果相同。

(base) yongqiang@yongqiang:~$ echo -e "\e[4m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\033[4m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -e "\033[4m yongqiang \033[0m"yongqiang
(base) yongqiang@yongqiang:~$

闪烁显示。

(base) yongqiang@yongqiang:~$ echo -e "\033[5m yongqiang \033[0m"yongqiang
(base) yongqiang@yongqiang:~$

红色字体，白色背景显示。

(base) yongqiang@yongqiang:~$ echo -e "\e[31;47m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$

1.8 `-E` - disable interpretation of backslash escapes (default)

禁用转义字符。

(base) yongqiang@yongqiang:~$ echo -e "\e[31;47m yongqiang \e[0m"yongqiang
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo -E "\e[31;47m yongqiang \e[0m"
\e[31;47m yongqiang \e[0m
(base) yongqiang@yongqiang:~$

1.9

(base) yongqiang@yongqiang:~$ echo yongqiang cheng
yongqiang cheng
(base) yongqiang@yongqiang:~$
(base) yongqiang@yongqiang:~$ echo yongqiang    cheng
yongqiang cheng
(base) yongqiang@yongqiang:~$

References

https://yongqiang.blog.csdn.net/