ShellCommand

Basic part

Echo printout

echo 'helloworld'

read Get user input

echo '请输入：'
read name
echo '你输入的是：' $name

Ls lists catalogs

ls

cat View file contents

cat package.json

Touch create File

touch test.sh

Echo writes to a file

echo test > test.sh

rm delete file

rm test.sh

Cd enters the directory

cd src

Return to the upper floor

cd ..

Rename a file

mv name1 name2

Take ownership of the folder

sudo chmod -R 777 .

Application chapter

One click to clean < none > image

docker rmi $(docker images | grep "<none>" | grep -oE "[0-9a-z]{12}" | tr '\n' ' ')

Description: docker images lists the images, grep none filters out the rows of the none images, then regularly extracts the image id, combines each line into a line with the tr command to separate spaces, and finally uses the rmi command to delete the filtered none image id

View file logs in real time

tail -f -n 10 logs/nest:09-16.log

View the version of a library in yarn.lock

cat yarn.lock | grep -oE -A1 "^react@\S+"  

Note: cat < file > can output the file content to the terminal, grep can filter each line of the terminal content,-o means only output matching content,-E means using extended regular,-A means that the output contains the next few lines, for example, A1 will contain the next line.

verification parameter

function verify_arg {
  if [ "$2" = "" ]; then
    echo "$1 is required: $2"
    exit
  else
    echo $2
  fi
}

verify_arg "entry" $entry

Conditional statement

Multiple lines:

if [[ "$entry" = "123" ]]; then
  echo $entry
else
  echo "test"
  exit
fi

Single line:

# exit 0 正常退出，exit 1 异常退出
[[ {{ .beta }} == true ]] && echo "skip register entry in beta." && exit 0

List folders

ls -d */

Grep filter rows

-v reverse election

ls -d */ | grep -v "blog" # 排除含有blog的

Pipeline cp

ls -d */ | grep -v "blog" | xargs -I {} cp -r ./{} ./blog/{} 

placeholder {}declares a placeholder {} to receive the previous value, followed by a command to replace the symbol

Delete files that are not of a certain type

find ./blog -type f -not -name "*.md" | xargs -I {} rm -rf {}

Delete empty directory

find ./blog -type d -empty | xargs -n 1 rm -rf

Take a few characters from each line

find . | awk '{print substr($0, 3)}' # 取每行第3个字符后的

Determine whether there is a specified content in the file

[[ $(grep -c build ./package.json) != 0 ]] && yarn run build

Delete all files in the directory (including hidden files)

ls -A1 | xargs rm -rf