Linux shell script read file line by line All In One

Linux shell 脚本逐行读取文件

I just want to replace thegrep command, and filter out the real IP address 192.168.18.195 with native shell syntax.

#!/usr/bin/env bash

IPs=$(ifconfig | grep -oE '192\.168\.(1?[0-9][0-9]?|2[0-4][0-9]|25[0-5])\.([2-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-4])\b')
echo $IPs
# 192.168.18.195

ifconfig.txt

en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        options=6463<RXCSUM,TXCSUM,TSO4,TSO6,CHANNEL_IO,PARTIAL_CSUM,ZEROINVERT_CSUM>
        ether a4:83:e7:91:62:79 
        inet6 fe80::1ca2:3b0a:df9d:465f%en1 prefixlen 64 secured scopeid 0x7 
        inet 192.168.18.195 netmask 0xffffff00 broadcast 192.168.18.255
        inet6 fd80:eae6:1258:0:37:7544:1d1:7b08 prefixlen 64 autoconf secured 
        nd6 options=201<PERFORMNUD,DAD>
        media: autoselect
        status: active

https://gist.github.com/xgqfrms/a9e98b17835ddbffab07dde84bd3caa5

IP

while..do..done bash loop

# 多个命令写在同一行上，需要使用 `;` 符号分割
while read -r line; do COMMAND; done < input.file

ip-filter.sh

#!/usr/bin/env bash

# 写死文件的绝对路径 👎
# input="/absolute/path/to/file.txt"

# 动态读取 参数 ✅
input=$1

# while IFS= read -r line
while read -r line
do
  echo "$line"
  # match regex ???
done < "$input"

$ bash ./ip-filter.sh ifconfig.txt
# OR
$ chmod +x ./ip-filter.sh
$ ./ip-filter.sh ifconfig.txt

https://www.cyberciti.biz/faq/unix-howto-read-line-by-line-from-file/

demos

sed filter IP

使用 sed 代替 grep

# sed regex❓

TODO fix sed ❌

#!/usr/bin/env bash

# 写死文件的绝对路径 👎
# input="/absolute/path/to/file.txt"

# 动态读取 参数 ✅
input=$1

rgexp='192\.168\.(1?[0-9][0-9]?|2[0-4][0-9]|25[0-5])\.([2-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-4])\b'

# while IFS= read -r line
while read -r line
do
  echo "$line"
  # match regex ???
  # rgexp.test($line)
  # echo "$line" | sed -e 's/rgexp//' -n
  # echo "$line" | sed -e 's/192\.168/✅/' -n
  # echo "$line" | sed -e 's/192\.168/✅/'
  # printf "$line" | sed -e 's/192\.168/✅/' > ./ip.md
  # printf "$line" | sed -e 's/192\.168/✅/' > ./ip.md
  # if echo "$line" | sed -e 's/192\.168/✅/' -n
  if echo "$line" | sed -e 's/192\.168/✅/'
  then
    echo "✅"
  else
    echo "❌"
  fi
done < "$input"


<<EOF
$ echo "this is abc" | sed -e 's/abc/xyz/'
this is xyz
# 不输出
$ echo "this is abc" | sed -e 's/abc/xyz/' -n

EOF


# $ ./ip-filter.sh ./ifconfig.txt

# https://www.cnblogs.com/xgqfrms/p/17362135.html

https://www.cnblogs.com/xgqfrms/p/16824934.html

# man sed
$ man sed

grep filter IP

$ ifconfig | grep -oE '192\.168\.(1?[0-9][0-9]?|2[0-4][0-9]|25[0-5])\.([2-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-4])\b'

$ ifconfig | grep -woE '192\.168\.(1?[0-9][0-9]?|2[0-4][0-9]|25[0-5])\.([2-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-4])'

$ ifconfig | grep -oE '192\.168\.(1?[0-9][0-9]?|2[0-4][0-9]|25[0-5])\.([2-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-4])[[:space:]]'

(🐞 反爬虫测试！打击盗版⚠️）如果你看到这个信息, 说明这是一篇剽窃的文章，请访问 https://www.cnblogs.com/xgqfrms/ 查看原创文章！

shell script `if then` / `else` / `elseif then` / `fi`

if else 的 [...] 判断语句中大于使用 -gt，小于使用 -lt。

如果使用 ((...)) 作为判断语句，大于和小于可以直接使用 > 和 <。

https://www.runoob.com/linux/linux-shell-process-control.html

shell script & multi-line comments

<<EOF & EOF

#!/usr/bin/env bash


# TODO: python3 & pip3 install checker
# if not installed then
#   # install promoto
#   echo "❌"
# else
#   echo "✅"
# fi

rm -rf ./python_package/dist/*.*

# ⚠️ 必须要先进入 python project package 的目录，才能执行构建打包和上传文件
cd ./python_package/
# && 串行
./build.sh && ./upload.sh

<<EOF
"""

# && 串行
./python_package/build.sh && ./python_package/upload.sh

ERROR Source /Users/xgqfrms-mm/Documents/github/math_package_project does not appear to be a Python project: no pyproject.toml or setup.py
build ✅
ERROR    InvalidDistribution: Cannot find file (or expand pattern): 'dist/*'
upload ✅

"""
EOF