#!/usr/bin/env bash ################### if 语句 ################### # 写成一行 if [[ 1 -eq 1 ]]; then echo "1 -eq 1 result is: true"; fi # Output: 1 -eq 1 result is: true # 写成多行 if [[ "abc" -eq "abc" ]] then echo ""abc" -eq "abc" result is: true" fi # Output: abc -eq abc result is: true ################### if else 语句 ################### if [[ 2 -ne 1 ]]; then echo "true" else echo "false" fi # Output: true ################### if elif else 语句 ################### x=10 y=20 if [[ ${x} > ${y} ]]; then echo "${x} > ${y}" elif [[ ${x} < ${y} ]]; then echo "${x} < ${y}" else echo "${x} = ${y}" fi # Output: 10 < 20