Linux shell script bug and error All In One

合集 - Linux Shell(69)

1.Linux shell command ln All In One2023-06-042.Linux shell command cut All In One2023-06-043.Linux shell standard input bugs All In One2023-05-314.Linux shell command base64 All In One2023-05-305.How to use the shell command to get the version of Linux Distributions All In One2023-05-306.Linux shell command make & Makefile All In One2023-05-247.Linux shell command strings All In One2023-05-248.sudo & su & Rust All In One2023-05-079.Linux shell command make All In One2023-05-0310.Linux shell script shebang env All In One2023-05-0311.Linux shell script switch...case All In One2023-05-0312.Linux shell command ls sort by date All In One2023-05-0213.Linux shell script read file line by line All In One2023-04-2814.Linux shell regular expression All In One2023-04-2715.How to fix IP filter regular expressions written using grep command in Linux shell script All In One2023-04-2616.Linux shell script programming All In One2023-04-2217.Linux shell script redirection All In One2023-04-2018.How to use Linux shell command filter the IP address All In One2023-04-1719.how to create one interactive mode command line configuration tool with shell language on Linux All In One2023-04-1420.Linux shell script get date and time All In One2023-04-1221.Linux shell command screen All In One2023-04-0922.Linux shell `#!` interpreter All In One2023-03-3023.Linux shell set command All In One2023-03-2524.Linux shell script auto generate batch files All In One2023-03-2425.Linux bash script HereDoc All In One2023-03-2426.Linux shell system environment variables All In One2023-02-1027.Linux shell command curl All In One2023-01-0928.Linux shell command chroot All In One2023-01-0429.Linux shell command chmod All In One2023-01-0230.Linux shell number variables add All In One2022-12-2831.Linux bash shell "${1}" All In One2022-12-2732.Linux xattr shell command All In One2022-12-2133.Multiple Ways to Change Terminal Shell in Linux All In One2022-11-3034.Linux shell stdin & stdout & stderr All In One2022-11-1835.Linux shell man command All In One2022-10-2636.Linux shell command line editor All In One2022-10-2537.Linux shell command uname All In One2022-08-1738.Linux bash shell script block comment All In One2022-06-1439.Linux bash shell script batch download files All In One2022-03-29

40.Linux shell script bug and error All In One2022-02-25

41.Linux bash write long string with multi-lines comments All In One2021-12-1642.Linux set command All In One2021-11-1143.Linux echo command All In One2021-10-1444.Linux echo 换行 All In One2021-10-1345.Linux Bash shell 脚本定时器 All In One2021-10-0946.Linux System Variables All In One2021-09-2447.linux bash shell auto read write template2021-03-2748.Linux bash script read args All In One2021-02-1949.Linux Bash Script conditions syntax All In One2021-01-2250.Linux Bash Script loop syntax All In One2021-01-2251.Linux shell script All In One2021-01-0652.如何通过 Linux terminal 查看一个文件的 meta 信息 All In One2020-09-2453.Linux shell uname -a All In One2020-09-0154.Linux shell command create file methods All In One2020-08-0955. how to write string to file in linux bash All In One2020-05-0656.linux bash shell & lsof & grep & ps2020-01-0857.Linux Bash Shell All In One2019-12-1758.Linux shell command copy file All In One2019-05-2959.Linux shell command & zip & tar All In One2018-09-2760.Linux shell command show project directory tree All In One2018-09-2661.Linux shell commands man chmod All In One2018-08-2862.Linux & bash & shell & PID & PPID2018-08-0763.Linux bash shell All In One2018-08-0664.Linux shell command symbolic link & soft link All In One2018-07-0465.Linux bash shell All In One2018-07-0366.Linux shell (.sh 文件) 基础命令 常用命令 汇总2016-04-0467.How to use a shell script to check whether a command had been installed in the Linux server All In One2023-09-2268.How to print a string with a variable by using the echo command in the shell script All In One2023-09-2169.Linux install vim errors All In One2023-05-29

收起

Linux shell script bug and error All In One

if [ "$condition1" == "$condition2" ] then echo yes; else echo no; fi

errors

未找到命令 ❌

1. shell 变量赋值=等号两边不能有空格

# ❌
var1 = 2023

# ✅
var1=2023
echo $var1
echo "$var1"
echo ${var1}

参数太多 ❌

2. 在 if 条件判断语句中， 使用双引号包裹变量

#!/usr/bin/env bash

function is_same_file () {
 echo "arg1 = $1"
 echo "arg2 = $2"
 # 赋值操作=等号两边不能有空格 ✅
 test1=$(stat -c "%d %i" $1)
 test2=$(stat -c "%d %i" $2)
 echo $test1
 echo $test2
 # "$var", 在 if 条件语句中， 使用双引号包裹变量 ✅
 # if 与 [ 之间有空格 ✅
 # [ condition ] 的两边有空格 ✅
 # if [ $test1 == $test2 ] ; then
 if [ "$test1" == "$test2" ]; then
  echo yes;
 else
  echo no;
 fi
}

is_same_file ./student.sh ./hard
is_same_file ./student.sh ./soft

variable assignment with spaces bug

#!/bin/sh

# WEEKLY_TITLE
# WEEKLY_DESC
# CONTENT

WEEKLY_TITLE='';
WEEKLY_DESC='';
CONTENT='';

HOUR=$(date +%H);
echo "现在时间是: ${HOUR}"

# number / string
# if [$HOUR == '14']
# if [$HOUR == 14]
# then
#     WEEKLY_TITLE="周报通知";
#     WEEKLY_DESC="⏰ 两点了，写周报啦 ✅";
#     echo "⏰ 两点了，写周报啦 ✅"
# else
#     WEEKLY_TITLE="周会通知";
#     WEEKLY_DESC="⏰ 五点了，开周会了";
#     echo "⏰ 五点了，开周会了"
# fi

bug ❌

# ❌ spaces bug
CONTENT2 = '
[
    {
        "tag": "text",
        "text": "日期: '$WEEKLY_DESC'\n"
    },
    {
        "tag": "at",
        "user_id": "all",
        "user_name": "所有人"
    } 
]'

echo "⏰ $CONTENT2"

solution ✅

# echo "⏰ '${CONTENT1}'"
echo "⏰ $CONTENT1'"
# ✅ no whitespaces ok
CONTENT2='
[
    {
        "tag": "text",
        "text": "日期: '$WEEKLY_DESC'\n"
    },
    {
        "tag": "at",
        "user_id": "all",
        "user_name": "所有人"
    } 
]'

echo "⏰ $CONTENT2"

if whitespace

if...then...else..fi

bug ❌

#!/bin/bash
 
# str1="Learn Bash"
# str2="Learn Bash with tutorialkart"
 
# if [ "$str1" != "$str2" ]; then
#     echo "Both Strings are not Equal. ❌"
# else
#     echo "Both Strings are Equal. ✅å"
# fi


HOUR=20;
echo "现在时间是: ${HOUR}"

TWO_O_CLOCK=14
# TWO_O_CLOCK='14'

# number / string 
# if [$HOUR == '14'] / if [$HOUR == 14]
# not space bug ❌
# if["$var1" == "$var2"] / if["$var1" != "$var2"]
if ["$HOUR" != "$TWO_O_CLOCK"]; then
    WEEKLY_TITLE="周报通知";
    WEEKLY_DESC="⏰ 两点了，写周报啦 ✅";
    echo "\n⏰ 两点了，写周报啦 ✅"
else
    WEEKLY_TITLE="周会通知";
    WEEKLY_DESC="⏰ 五点了，开周会了❌";
    echo "\n⏰ 五点了，开周会了❌"
fi

# space ok ✅
# if[ "$var1" == "$var2" ] / if[ "$var1" != "$var2" ]
if [ "$HOUR" != "$TWO_O_CLOCK" ]; then
    WEEKLY_TITLE="周报通知";
    WEEKLY_DESC="⏰ 两点了，写周报啦 ✅";
    echo "\n⏰ 两点了，写周报啦 ✅"
else
    WEEKLY_TITLE="周会通知";
    WEEKLY_DESC="⏰ 五点了，开周会了❌";
    echo "\n⏰ 五点了，开周会了❌"
fi

solution ✅

#!/bin/bash
 
# str1="Learn Bash"
# str2="Learn Bash with tutorialkart"
 
# if [ "$str1" != "$str2" ]; then
#     echo "Both Strings are not Equal. ❌"
# else
#     echo "Both Strings are Equal. ✅å"
# fi


HOUR=20;
echo "现在时间是: ${HOUR}"

TWO_O_CLOCK=14
# TWO_O_CLOCK='14'

# number / string 
# if [$HOUR == '14'] / if [$HOUR == 14]

demos

tutorials

https://www.tutorialkart.com/bash-shell-scripting/bash-strings-equal/

https://www.gnu.org/software/bash/manual/html_node/Bash-Conditional-Expressions.html

refs

https://github.com/xgqfrms/linux-shell-script-programming/issues/3#issuecomment-1578070809

https://stackoverflow.com/questions/76408365/why-does-the-linux-shell-command-test-ef-not-work-on-soft-links-as-its-manual-d/76408633#76408633

---

---

©xgqfrms 2012-2025

www.cnblogs.com/xgqfrms 发布文章使用：只允许注册用户才可以访问！

原创文章，版权所有©️xgqfrms, 禁止转载 🈲️，侵权必究⚠️！

---