shell常用代码

shell常用代码：

判断是否使用sudo

# root or not
if [[ $EUID -ne 0 ]]; then
  SUDO='sudo -H'
else
  SUDO=''
fi

$SUD0 apt update -y

EUID: 在shell启动时被初始化的当前用户的有效ID,如果是root用户EUID=0
shell命令id -u作用相同

${:-}变量的默认值

1	NUM_THREADS=${NUM_THREADS:-4}

如果NUM_THREADS变量没有被定义，NUM_THREADS值将是：-后得默认值；如果NUM_THREADS变量被定义，NUM_THREADS值将定义值

=====>$bash -v aa.sh
#!/bin/bash
NUM_THREADS=${NUM_THREADS:-4}
echo "num-thread=$NUM_THREADS"
num-thread=4

=====>$bash -v aa.sh
#!/bin/bash
NUM_THREADS=8
NUM_THREADS=${NUM_THREADS:-4}
echo "num-thread=$NUM_THREADS"
num-thread=8

将逗号分隔的字符串转成换行

OLD_IFS="$IFS"
IFS=","
arr=(`cat 1.txt`)
IFS="$OLD_IFS"
for s in ${arr[@]}
do
    echo $s | tr -d '"'
done

多线程

#!/bin/sh

cpu_tmp=0
cpu=""
pmon=""
cycles=0
data_dir="test_rpt.$$"

while read LINE
do
	if echo $LINE|grep 'cpu_tmp'
	then
		cpu_tmp=${LINE#*:}
	fi


	if echo $LINE|grep 'cycles'
	then
		cycles=${LINE#*:}
	fi

done < run.cfg

#多线程：
# init fifo file
THREAD1DIR=3 && FIFONR=4 && FIFONAME="$$.ff" && mkfifo $FIFONAME && str="exec $FIFONR<> $FIFONAME" && eval $str && rm $FIFONAME -f
i=0
while [ $i -lt $THREAD1DIR ]; do
	i=$((i+1))
	echo
done >& $FIFONR
#for (( i=0; i<$THREAD1DIR; i++ )); do

# start test 1st level dir
all=`find . -maxdepth 1 -name "?????\.*"`
for i in $all
do
	if [ -d $i ]
	then
		read
		( echo $i" 1runing" && cd $i/ && ./$i'.run'.sh $cycles && cd - && echo >& $FIFONR ) &
	fi
done <& $FIFONR

# rm fifo file
wait && str="exec $FIFONR>&-" && eval $str

#get log
[ -d $data_dir ] && rm -rf $data_dir || mkdir $data_dir && cp run.cfg $data_dir -f

for i in $all
do
	if [ -d $i ]
	then
		des_dir=$data_dir'/'$i'/'
		mkdir $des_dir
		src_dir='./'$i'/'
		file_path=`find $src_dir/ -name *_*.log`
		echo $file_path
		mv $file_path $des_dir
	fi
done
chmod 777 './'$data_dir -R
rm *.ff -f

修改文件名后缀

for file in `find . -name "*.f90"`
do
	newfile=${file%.*}.f77
	#echo "$newfile"
	mv $file $newfile
done

Linux批量更改文件后缀名

检查网段IP占用情况

#!/bin/bash

up=0
down=0

for siteip in $(seq 1 255)
do
	#site="192.168.2.${siteip}"
	site="172.16.189.${siteip}"
	ping -c1 -W1 ${site} &> /dev/null
	if [ "$?" == "0" ]; then
		up=$[$up+1]
		echo "$site is UP, cnt=$up"
	else
		down=$[$down+1]
		echo "$site is DOWN, cnt=$down"
	fi
done
# 除法
alive=`awk 'BEGIN{printf "%.2f\n",('$up'/'$(($up + $down))')}'`

echo "up:$up, down:$down, alive:$alive"

提取本地IP

1	ip=`ifconfig \| grep "inet " \| grep -v "127.0.0.1"\| awk '{print $2}'`

-v: 排除

参考

[shell中各种括号的作用()、(())、[]、[]]、{}
shell变量详解