linux echo 输出字符与变量 查看echo的帮助内容

ECS信息

• 规格：2vCPUs | 4GiB | kc1.large.2
• 镜像：openEuler 20.03 64bit with ARM | 公共镜像

linux echo 输出字符与变量 查看echo的帮助内容

echo 输出字符变量

# echo $SHELL
/bin/bash

# echo hello world
hello world

查看echo的帮助内容

• 正确示范

# /bin/echo --help
Usage: /bin/echo [SHORT-OPTION]... [STRING]...
  or:  /bin/echo LONG-OPTION
Echo the STRING(s) to standard output.

  -n             do not output the trailing newline
  -e             enable interpretation of backslash escapes
  -E             disable interpretation of backslash escapes (default)
      --help     display this help and exit
      --version  output version information and exit

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

  \\      backslash
  \a      alert (BEL)
  \b      backspace
  \c      produce no further output
  \e      escape
  \f      form feed
  \n      new line
  \r      carriage return
  \t      horizontal tab
  \v      vertical tab
  \0NNN   byte with octal value NNN (1 to 3 digits)
  \xHH    byte with hexadecimal value HH (1 to 2 digits)

NOTE: your shell may have its own version of echo, which usually supersedes
the version described here.  Please refer to your shell's documentation
for details about the options it supports.

GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/echo>
or available locally via: info '(coreutils) echo invocation'

• 错误示范

# echo -?
-?

# echo --help
--help

# echo

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