Shell Script Learning (1)

Format:

#!/bin/bash: Flag a shell script

#Filename: first_shell.sh: File name

#auto: echo "Hello Shell": role

#by author h0f 2018-03-08: Author-date

echo "Hello Shell": Execute content

Execution: chmod o+x first_shell.sh

./first_shell.sh

Or:/bin/bash first_shell.sh

echo $? Determine if the last command was successful

Echo-e "\033[32mpleasse Select menu follow: \033[1m" color adjustment

/bin/bash 1_shell.sh

If Judgment statement number size

Determine if the file exists:

The first time does not exist, then creates, the second execution shows the existence OK

Note: 1 "." The same functionality as the source command, read-in script and execute script

Note: 2. Brackets [] must have at least one space at each end, as well as double brackets [[]]

3. The value of the string definition variable for a regular variable should be double-quoted, and there must be no spaces before and after the equals sign, which requires a strong reference (referred to as a WYSIWYG character reference) to use single quotation marks (").

If it is a reference to the command, use the back quotation marks (• ）。

4. Single quotes, double quotes, and anti-quotes in all scripts must be symbols in the English state.

Shell Script Learning (1)