利用xargs实现多任务并发

利用xargs实现多任务并发

[4aiur@localhost Temp]$ echo 127.0.0.1 192.168.2.50 192.168.10.108 | xargs -n1 -P2 -I % ping -c 3 %
PING 127.0.0.1 (127.0.0.1): 56 data bytes
64 bytes from 127.0.0.1: icmp_seq=0 ttl=64 time=0.048 ms
PING 192.168.2.50 (192.168.2.50): 56 data bytes
64 bytes from 192.168.2.50: icmp_seq=0 ttl=64 time=0.026 ms
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.091 ms
64 bytes from 192.168.2.50: icmp_seq=1 ttl=64 time=0.022 ms
64 bytes from 192.168.2.50: icmp_seq=2 ttl=64 time=0.039 ms
64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.077 ms

--- 192.168.2.50 ping statistics ---
3 packets transmitted, 3 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.022/0.029/0.039/0.007 ms

--- 127.0.0.1 ping statistics ---
3 packets transmitted, 3 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.048/0.072/0.091/0.018 ms
PING 192.168.10.108 (192.168.10.108): 56 data bytes
64 bytes from 192.168.10.108: icmp_seq=0 ttl=63 time=6.244 ms
64 bytes from 192.168.10.108: icmp_seq=1 ttl=63 time=1.392 ms
64 bytes from 192.168.10.108: icmp_seq=2 ttl=63 time=1.062 ms

--- 192.168.10.108 ping statistics ---
3 packets transmitted, 3 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 1.062/2.899/6.244/2.369 ms
[4aiur@localhost Temp]$

使用xargs扫描同网段内存活的设备

[4aiur@localhost Temp]$ for ((x=1; x/dev/null | awk /ttl/'{print $4}'

Tags: shell

目录名大小写转换

使用find把目录名修改为大写——-

find . -type d | sort -r |\
while read name
do
   echo "mv $name ${name%/*}/echo ${name##*/} | tr '[:lower:]' '[:upper:]'"
   mv $name ${name%/*}/echo ${name##*/} | tr '[:lower:]' '[:upper:]'
done

使用递归方式把目录名修改为小写

#!/bin/bash
# set -x

tolower () {
   ls | while read name
   do
       if [ -d $name ] ; then
           new_name=echo $name | tr "[:upper:]" "[:lower:]"
           if [[ $name != $new_name ]] ; then
               mv $name $new_name
           fi
           cd $new_name
           tolower
       fi
   done
}
tolower

Tags: shell

摘自www.commandlinefu.com的一些命令

摘自www.commandlinefu.com的一些命令

# change to the previous working directory
$ cd -

# quickly backup or copy a file with bash
$ cp filename{,.bak}

# mtr, better than traceroute and ping combined
# mtr combines the functionality of the traceroute and ping programs in a single network diagnostic tool.
# As mtr starts, it investigates the network connection between the host mtr runs on and HOSTNAME. by sending packets with purposly low TTLs. It continues to send packets with low TTL, noting the response time of the intervening routers. This allows mtr to print the response percentage and response times of the internet route to HOSTNAME. A sudden increase in packetloss or response time is often an indication of a bad (or simply over‐loaded) link.
$ mtr google.com

# Salvage a borked terminal
# If you bork your terminal by sending binary data to STDOUT or similar, you can get your terminal back using this command rather than killing and restarting the session. Note that you often won't be able to see the characters as you type them.
$ reset

# Empty a file
# For when you want to flush all content from a file without removing it (hat-tip to Marc Kilgus).
$ > file.txt

Tags: shell