Linux的bash命令语法

可用点

#!/bin/bash
# 文件要以上面开始,.sh结尾的文件不需要

# 赋权文件可执行权限
chmod +x <fileName>

# 获取java jar包启动的进程id
ps -ef | grep *.jar | grep -v grep | awk '{print $2}'

shell变量

变量命令规则：

只能包含字母、数字、下划线；
不能以数字开口，可以包含数字；
不能使用Shell的关键字作为变量名
使用大写字母表示常量；
变量赋值不能使用空格，例如：PID=“pid”；

使用变量

#!/bin/bash
PID="pid"
P1=`ps -ef | grep *.jar | grep -v grep | awk '{print $2}'` # 1.使用命令执行结果作为变量
P1=`ps -ef | grep *.jar | grep -v grep | awk "{print $2}"` # 1.使用命令执行结果作为变量
P2="`ps -ef | grep *.jar | grep -v grep | awk '{print $2}'`" # 1.使用命令执行结果作为变量
PID=$(ps -ef | grep *.jar | grep -v grep | awk '{print $2}') # 2.# 使用变量
echo $PID
echo "P1=$PID"
echo 'P2=$PID'
echo 'P3=''$PID' # 要成对
echo ${PID}# 设置只读
only_read="Java"
readonly only_read
only_read="python" #会有提示# 删除变量
unset only_read
echo ${only_read}

在这里插入图片描述

变量类型

# 字符串变量
s1="Hello World"
s2='Hello World'# 整数变量
declare -i i1=128# 数组变量
array_example=(1 2 3 4 5)
declare -A accociative_array
accociative_array["name"]="zs"
associative_array["age"]=18# 读取环境变量
echo $JAVA_HOME

流程语句

if

#!/bin/sh
if [ condition ]; then# ...
else# ...
fi

#!/bin/sh

运算符

#!/bin/sh###
SERVICE_NAME="lgsa-portRelease-mgr"ENVFILE="../env"PIDFILE="pid"checkRunning(){if [ -f "$PIDFILE" ]; thenif  [ -z "`cat $PIDFILE`" ];thenecho "ERROR: Pidfile '$PIDFILE' exists but contains no pid"return 2fiPID="`cat ${PIDFILE}`"RET="`ps -p "${PID}"|grep java`"if [ -n "$RET" ];thenecho "${RET}"return 1;elsereturn 0;fielsereturn 0;fi
}status(){if ( checkRunning );thenPID="`cat $PIDFILE`"echo "'$SERVICE_NAME' is running (pid '$PID')"exit 0fiecho "'$SERVICE_NAME' not running"exit 1
}#启动方法
start(){if ( checkRunning );thenPID="`cat $PIDFILE`"echo "INFO: Process with pid '$PID' is already running"exit 0fiENVIRONMENT="`cat ${ENVFILE}`"java -jar -Xms64M -Xmx512M -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5105 -Dspring.config.location=config-${SERVICE_NAME}/application-${ENVIRONMENT}.yml -Dlogging.config=config-${SERVICE_NAME}/log4j2.xml  ${SERVICE_NAME}-0.0.1-SNAPSHOT.jar --spring.profiles.active=${ENVIRONMENT} > console.log 2>&1 &echo $! > "${PIDFILE}";
}
#停止方法
stop(){if ( checkRunning ); thenPID="`cat ${PIDFILE}`"echo "INFO: sending SIGKILL to pid '$PID'"kill -KILL $PIDRET="$?"rm -f "${PIDFILE}"return $RETfiecho "INFO: not running, nothing to do"return 0
}show_help() {cat << EOF
Tasks provided by the sysv init script:stop            - terminate instance in a drastic way by sending SIGKILLstart           - start new instancerestart         - stop running instance (if there is one), start new instancestatus          - check if '$SERVICE_NAME' process is running
EOFexit 1
}# show help
if [ -z "$1" ];thenshow_help
ficase "$1" instatus)status;;restart)if ( checkRunning );then$0 stopechofi$0 start$0 status;;start)start;;stop)stopexit $?;;*)
esac