Shell小技巧

安哥网络

1. 用&& ||简化if elsegzip -t a.tar.gz if [[ 0 == $? ]]; then     echo "good zip" else     echo "bad zip" fi 可以简化为：
gzip -t a.tar.gz && echo "good zip" || echo "bad zip"2. 命令行参数解析while getopts ":a:b:c" OPT; do     case $OPT in         a) arg_a=$OPTARG";;         b) arg_b=$OPTARG;;         c) arg_c=true;;         ?) ;;     esac done shift $((OPTIND-1))3. 获取文件大小$ stat -c %s fw8ben.pdf4. 字符串替换替换第一个：${string//pattern/replacement} 替换全部：${string//pattern/replacement} $ a='a,b,c' $ echo ${a//,/ /} a b c5. Contains子字符串？string='My string' if [[ $string == *My* ]]; then     echo "It's there!" fi6. 重定向1>File 2>&17. 备份rsync -r -t -v /source_folder /destination_folder rsync -r -t -v /source_folder [user@]host:/destination_folder  注：命令执行后destinationfolder内将包含一个名为sourcefolder的目录。
8. 批量rename#为所有的txt文件加上.bak后缀： rename '.txt' '.txt.bak' *.txt #去掉所有的bak后缀： rename '.bak' '' *.bak9. 字符集设置echo $LANG /etc/sysconfig/i18n10. for/while循环for ((i=0; i < 10; i++)); do echo $i; done for line in $(cat a.txt); do echo $line; done for f in *.txt; do echo $f; done while read line ; do echo $line; done < a.txt cat a.txt | while read line; do echo $line; done11. 进程终止pkill swiftfox #根据名称终止进程 kill -9 <pid> #根据pid终止进程12. findfind ~/tmp -name "*abc*.txt" -mtime -5 #在~/tmp目录下查找名为*abc*.txt且修改时间为5天内的文件13. 删除空行cat a.txt | sed -e '/^$/d' $ (echo "abc "; echo ""; echo "ddd";) | awk '{ if(0!=NF) print $0;}'14. 比较文件修改时间[[ file1.txt -nt file2.txt ]] && echo true || echo false #-nt means "newer than"15. 定时关机# -t 10: warning与kill signal的间隔时间10s；+30: 分钟后定时关机nohup shutdown -t 10 +30 &            16. 模式提取$echo '2011-07-15 server_log_123.log hello world' | grep -o 'server_log_[0-9]\+\.log'            server_log_123.log $echo '2011-07-15 server_log_123.log hello world' | sed 's/.*\(server_log_.*\.log\).*/\1/'            server_log_123.log17. DOS转Unix$cat a.txt | tr -d '' $dos2unix a.txt
18.实现Dictionary结构hput() {     eval "hkey_$1"="$2" }hget() {     eval echo '${'"hkey_$1"'}' }$ hput k1 aaa$ hget k1aaa19.去掉第二列$ echo 'a b c d e f' | cut -d ' ' -f1,3-a c d e f20.把stderr输出保存到变量$ a=$( (echo 'out'; echo 'error' 1>&2) 2>&1 1>/dev/null) $ echo $aerror21.删除前3行$cat a.txt | sed 1,3d22.大小写转换$ echo $foo | tr '[:lower:]' '[:upper:]'$ tr ‘[A-Z]’ ‘[a-z']’ < foo.txt23.读取多个域到变量$ read a b c <<< “xxx yyy zzz”$ echo $byyy24.遍历数组array=( one two three ) for i in ${array[@]} do     echo $i done25.查看硬盘使用情况$ df –h26.查看目录大小$ du –sh ~/apps27.查看CPU信息$ cat /proc/cpuinfo28.date$ date +%Y-%m-%d2012-12-24$ date +%Y-%m-%d –date ‘-1 day’2012-12-23$ date +%Y-m-%d –date ‘Dec 25’2011-12-25$ date +%Y-m-%d –date ‘Dec 25 – 10 days’2011-12-1529.svn1) 启动svn daemon
$ svnserve –d –r <svn_home>30.添加sudoers$ vim /etc/sudoers31.获取路径名和文件名$ dirname ‘/home/todd/a.txt’/home/todd$ basename ‘/home/todd/a.txt’a.txt32. 查看用户最近登录时间$ finger weidagang[weidagang@localhost ~]$ finger weidagang Login: weidagang                        Name: weidagang Directory: /home/weidagang              Shell: /bin/bash On since Sat Jan  7 14:15 (CST) on pts/2 from 10.69.22.14133.常用网络配置文件和命令[网卡]配置文件：/etc/sysconfig/network-scripts/ifcfg-<i/f name><静态IP分配实例>DEVICE=eth0 ONBOOT=yes BOOTPROTO=static IPADDR=192.168.168.11 NETMASK=255.255.255.0 GATEWAY=192.168.168.252<DHCP实例>ONBOOT=yes TYPE=Ethernet DHCP_HOSTNAME=sleipnir.cullen.lesbell.com.au DEVICE=eth0 HWADDR=00:0c:6e:0a:3d:26 BOOTPROTO=dhcp USERCTL=no PEERDNS=yes查看网卡状态：ifconfig改变网络状态：<CentOS>service network {start|stop|restart|reload|status} 或 /etc/init.d/network {start|stop|restart|reload|status}<Ubuntu>/etc/init.d/networking restart[DNS]配置文件：/etc/resolv.confsearch cullen.lesbell.com.au lesbell.com.au nameserver 192.168.168.1 nameserver 192.168.168.252查看域名解析结果：nslookup[Host]配置文件：/etc/hosts192.168.0.15 todd[ARP]查看arp cache命令：arp –a[路由]查看路由：netstat -nr查看和修改路由表命令：route跟踪路由：traceroute34. 查看占用某端口的进程ID和程序名$ netstat --tcp -l -n -p | grep 3306tcp    0    0    127.0.0.1:3306    0.0.0.0:*    LISTEN    27238/mysqld35. 查看和修改主机名$ echo $HOSTNAME$ echo /proc/sys/kernel/hostname$ vim /etc/sysconfig/network36. 文件内容比较$ cat file1.txtaaabbbccc$cat file2.txtbbbcccddd#搜索仅出现在file1.txt中的行$ comm –2 –3 file1.txt file2.txtaaa#搜索file1.txt和file2.txt都出现的行$ comm –1 –2 file1.txt file2.txtbbbccc37. awk复杂分隔符# 多字符作分隔符$ echo "a||b||c||d" | awk -F '[|][|]' '{print $3}'c# 多种分隔符1$echo "a||b,#c d" | awk -F '[| ,#]+' '{print $4}'d# 多种分隔符2$echo "a||b##c|#d" | awk -F '([|][|])|([#][#])' '{print $NF}'c|#d38. openssl# 加密文件$ openssl aes-256-cbc -a -salt -in secrets.txt -out secrets.txt.enc# 解密文件$ openssl aes-256-cbc -d -a -in secrets.txt.enc -out secrets.txt.new39. 删除最后一行末尾的分隔符删除下面a.txt中最后一行的逗号：
a.txt========================pmNoOfSwDownHsCong, pmUlUpswitchAttemptHigh, pmUlUpswitchAttemptLow, pmUlUpswitchSuccessHigh, pmUlUpswitchSuccessLow, pmUpswitchFachHsAttempt, pmUpswitchFachHsSuccess, ========================$ cat a.txt | sed '$s/,$//'40. 文本和二进制数转换文本进制转换
$ echo "ibase=16;1F" | bc31$ echo "obase=16;31" | bc1F$ printf "%x" 4095fff$ printf "%.8x" 409500000fff$ printf "%d" 0xfff4095$ printf "%.6d" 0x000fff004095文本转二进制数
# big endianness$ printf "0: %.8x" "65534" | xxd -r -g0 >a.bin$ xxd a.bin0000000: 0000 fffe# little endianness$ printf "0: %.8x" 65534 | sed -e 's/0\: \(..\)\(..\)\(..\)\(..\)/0\: \4\3\2\1/' | xxd -r -g0 > a.bin$ xxd a.bin0000000: feff 0000

摘自：http://www.cnblogs.com/weidagang ... /04/05/2005731.html