shell 脚本常用调试方法

sh 命令调试选项（推荐）

使用方法：
字符串读取脚本。

$ sh -c 'if [ 1 -lt 2 ];then echo "true"; else echo "false"; fi'true

注：临时测试 shell 语法或者小段脚本时使用。
检查脚本是否存在语法错误。

$ sh -n daodaotest.sh

跟踪调试 shell 脚本，将执行的每一条命令结果依次打印出来。

$ sh -x daodaotest.sh+ '[' 2 -lt 2 ']'+ COUNT=3+ PARAMETER=daodaotest+ (( i = 1 ))+ (( i <= 3 ))+ echo '第 1 遍打印：daodaotest'第 1 遍打印：daodaotest+ (( i++ ))+ (( i <= 3 ))+ echo '第 2 遍打印：daodaotest'第 2 遍打印：daodaotest+ (( i++ ))+ (( i <= 3 ))+ echo '第 3 遍打印：daodaotest'第 3 遍打印：daodaotest+ (( i++ ))+ (( i <= 3 ))+ exit 0

跟踪调试 shell 脚本，将执行的每一条命令和结果依次打印出来。

$ sh -xv daodaotest.sh#!/bin/bash# 调试脚本示例# 使用方法usage() {  echo "Usage: sh $0 COUNT PARAMETER"  echo "t COUNT 循环打印次数"  echo "t PARAMETER 打印字符串"  echo "示例："  echo "t 1. 打印 daodaotest 2 次"  echo "t sh $0 2 daodaotest"}# 判断参数if [ $# -lt 2 ];then  usage  exit 1fi+ '[' 2 -lt 2 ']'# 打印次数COUNT=$1+ COUNT=3# 打印字符串PARAMETER=$2+ PARAMETER=daodaotest# 循环打印for (( i = 1; i <= $COUNT; i++));doecho "第 $i 遍打印：$PARAMETER"done+ (( i = 1 ))+ (( i <= 3 ))+ echo '第 1 遍打印：daodaotest'第 1 遍打印：daodaotest+ (( i++ ))+ (( i <= 3 ))+ echo '第 2 遍打印：daodaotest'第 2 遍打印：daodaotest+ (( i++ ))+ (( i <= 3 ))+ echo '第 3 遍打印：daodaotest'第 3 遍打印：daodaotest+ (( i++ ))+ (( i <= 3 ))exit 0+ exit 0

注：本人最常用-x参数，能解决 90% 的脚本调试问题。

set 方法

在脚本中用set命令。

使用方法：

$ cat daodaotest.shset -xv..... 省略set +xv$ sh daodaotest.sh 2 daodaotest# 使用方法usage() {  echo "Usage: sh $0 COUNT PARAMETER"  echo "t COUNT 循环打印次数"  echo "t PARAMETER 打印字符串"  echo "示例："  echo "t 1. 打印 daodaotest 2 次"  echo "t sh $0 2 daodaotest"}# 判断参数if [ $# -lt 2 ];then  usage  exit 1fi+ '[' 2 -lt 2 ']'# 打印次数COUNT=$1+ COUNT=2# 打印字符串PARAMETER=$2+ PARAMETER=daodaotest# 循环打印for (( i = 1; i <= $COUNT; i++));doecho "第 $i 遍打印：$PARAMETER"done+ (( i = 1 ))+ (( i <= 2 ))+ echo '第 1 遍打印：daodaotest'第 1 遍打印：daodaotest+ (( i++ ))+ (( i <= 2 ))+ echo '第 2 遍打印：daodaotest'第 2 遍打印：daodaotest+ (( i++ ))+ (( i <= 2 ))exit 0+ exit 0

注: 在脚本非常复杂时，set可以进行局部调试，在需要调试的代码块前后设置即可。

工具

shellcheck

shell 脚本静态检查工具，可以帮助你写出刚好的脚本。

官 ：
https://www.shellcheck.net/

手册：
https://github.com/koalaman/shellcheck

使用方法：

$ shellcheck daodaotest.shIn daodaotest.sh line 8:  echo "t COUNT 循环打印次数"       ^---------------^ SC2028: echo may not expand escape sequences. Use printf.In daodaotest.sh line 9:  echo "t PARAMETER 打印字符串"       ^------------------^ SC2028: echo may not expand escape sequences. Use printf.In daodaotest.sh line 11:  echo "t 1. 打印 daodaotest 2 次"       ^-----------------------^ SC2028: echo may not expand escape sequences. Use printf.In daodaotest.sh line 12:  echo "t sh $0 2 daodaotest"       ^---------------------^ SC2028: echo may not expand escape sequences. Use printf.In daodaotest.sh line 28:for (( i = 1; i <= $COUNT; i++));                   ^----^ SC2004: $/${} is unnecessary on arithmetic variables.For more information:  https://www.shellcheck.net/wiki/SC2028 -- echo may not expand escape sequen...  https://www.shellcheck.net/wiki/SC2004 -- $/${} is unnecessary on arithmeti...

BASH Debugger

bashdb 是一个类 GDB 的调试工具，可以运行断点设置、变量查看等常见调试操作。

官 ：
http://bashdb.sourceforge.net/

常用参数：

h：查看帮助。help 命令：命令的具体信息。n：执行下一条语句。s n：单步执行 n 次。b n：在行  n 处设置断点。c n：一直执行到行  n 处。l：显示上下文代码。print：打印变量值，例如 print $COUNT。finish：执行到程序最后或断点处。q or exit：退出。R：重新执行。

使用方法：

$ bashdb --debug daodaotest.sh bash debugger, bashdb, release 5.0-1.1.2Copyright 2002-2004, 2006-2012, 2014, 2016-2019 Rocky BernsteinThis is free software, covered by the GNU General Public License, and you arewelcome to change it and/or distribute copies of it under certain conditions.(/Users/jlh/tmp/daodaotest.sh:15):15:    if [ $# -lt 2 ];# 执行下一条语句。bashdb<0> n(/Users/jlh/tmp/daodaotest.sh:22):22:    COUNT=$1# 显示上下文代码。bashdb<1> l 17:      usage 18:      exit 1 19:    fi 20: 21:    # 打印次数 22: => COUNT=$1 23:    # 打印字符串 24:    PARAMETER=$2 25: 26:    # 循环打印# 单步执行 3 次。bashdb<2> s 3(/Users/jlh/tmp/daodaotest.sh:27):27:    for (( i = 1; i <= $COUNT; i++));((i <= 3))bashdb<3> l 22:    COUNT=$1 23:    # 打印字符串 24:    PARAMETER=$2 25: 26:    # 循环打印 27: => for (( i = 1; i <= $COUNT; i++)); 28:    do 29:    echo "第 $i 遍打印：$PARAMETER" 30:    done 31:# 打印 $COUNT 参数值bashdb<4> print $COUNT3# 执行到最后bashdb<5> finish第 1 遍打印：daodaotest第 2 遍打印：daodaotest第 3 遍打印：daodaotestDebugged program terminated normally. Use q to quit or R to restart.# 退出bashdb<6> qbashdb: That's all, folks...