21 Sep 2022
read是将标准输入中读取逻辑行，然后将其转换成一个或多个变量的工具。一般是从文件中读取内容，然后赋值给shell脚本的变量。
变量：
IFS: 逻辑行中用于分隔不同field的分隔符其他变量参见 read manual
选项：
-r: 把转义符\当做普通字符。配置文件内容：var.conf
cat << EOF > var.conf id=01 type=apple EOF
读取配置的shell脚本：load_var.sh
#!/bin/bash # read content from conf file and transfer it to var value pair in shell script # # EXAMPLE: # # var.conf's content # ================================== # id=01 # type=apple # ================================== # # this script will read one line each time, # for example the first line "id=01", and # separate it by "=", load the two part to # var key and value: # key=id; value=01 # then transfer it to new var pair in script # id=01 set -e while IFS='=' read -r key value do # ensure key and value is not empty if [[ -z ${key} ]] || [[ -z ${value} ]]; then continue fi # assign the content of var value to var which name is the content of var key # EXAMPLE: # orinal vars: key=foo; value=bar # new var: foo=bar if [[ ${key} == "id" ]] || [[ ${key} == "type" ]]; then eval "$key=$value" fi done < ./var.conf printf " id = %s\ntype = %s\n" ${id} ${type}
执行后的输出演示
sh load_var.sh id = 01 type = apple