linux shell script program intro

we base on linux cmd

#!/bin/bash
ls abc
mkdir abc
cd abc

function

#!/bin/bash
force=$1
function runNodeActivity(){
    echo 'runNode with pm2' $1
    cd /var/git/finance/fin_koala_activity
    pm2 start bin/processes_beta.json
}

parameter

$# 是传给脚本的参数个数 $0 是脚本本身的名字 $1是传递给该shell脚本的第一个参数 $2是传递给该shell脚本的第二个参数 $@ 是传给脚本的所有参数的列表

parameter in function

function tips(){
    echo 'perhaps you can now run:'
    echo 'cd /var/git/finance/fin_sails_koala'
    echo 'pm2 start bin/processes_beta.json'
    if [ $force == "-f" ];
    then 
        runSails
        
    fi
}

better to have help function

function help(){
echo ""
    echo "Examples: to run pm2 in fin_sails_koala"
    echo "$0 -f "
    echo "Examples: to kill pm2 in gentoo"
    echo "$0"
    exit
}

if then else

pm2count=`ps -ef| grep PM2 |wc -l`
if [ $pm2count -lt 2 ];
then
    echo 'there are less than 2 pm2 daemon, you can use it'
    tips
    exit 0
fi

debug

[debug in shell][1]