100 行 shell 写个 Docker

#    nsenter: 加入指定进程的指定类型的namespace中，然后执行参数中指定的命令。#       命令格式：nsenter [options] [program [arguments]]#       示例：nsenter –t 27668 –u –I /bin/bash##    unshare: 离开当前指定类型的namespace,创建且加入新的namesapce,然后执行参数中执行的命令。#       命令格式：unshare [options] program [arguments]#       示例：unshare --fork --pid --mount-proc readlink /proc/self##    ipcmk：创建shared memory segments, message queues, 和semaphore arrays#       参数-Q：创建message queues#    ipcs：查看shared memory segments, message queues, 和semaphore arrays的相关信息#      参数-a：显示全部可显示的信息#      参数-q：显示活动的消息队列信息

#查看当前shell的uts / ipc namespace number # readlink /proc/$$/ns/uts /proc/$$/ns/ipcuts:[4026531838]ipc:[4026531839] #查看当前主机名# hostnamemyCentos #查看ipc message queues,默认情况下没有message queue# ipcs -q ------ Message Queues --------key        msqid      owner      perms      used-bytes   messages     #创建一个message queue# ipcmk -QMessage queue id: 131072# ipcs -q ------ Message Queues --------key        msqid      owner      perms      used-bytes   messages   0x82a1d963 131072     root       644        0            0  -----> 切换至shell B执行------------------------------------------------------------------ #回到shell A之后我们可以看下hostname、ipc等有没有收到影响# hostnamemyCentos # ipcs -q ------ Message Queues --------key        msqid      owner      perms      used-bytes   messages   0x82a1d963 131072     root       644        0            0           #接下来我们尝试加入shell B中新的Namespace# nsenter -t 30372 -u -i /bin/bash [root@shell-B:/root]# hostnameshell-B # readlink /proc/$$/ns/uts /proc/$$/ns/ipcuts:[4026532382]ipc:[4026532383] # ipcs -q ------ Message Queues --------key        msqid      owner      perms      used-bytes   messages   #可以看到我们已经成功的加入到了新的Namespace中

#确认当前shell和shell A属于相同Namespace # readlink /proc/$$/ns/uts /proc/$$/ns/ipcuts:[4026531838]ipc:[4026531839] # ipcs -q ------ Message Queues --------key msqid owner perms used-bytes messages0x82a1d963 131072 root 644 0 0 #使用unshare创建新的uts和ipc Namespace，并在新的Namespace中启动bash # unshare -iu /bin/bash #确认新的bash uts/ipc Namespace Number # readlink /proc/$$/ns/uts /proc/$$/ns/ipcuts:[4026532382]ipc:[4026532383] #设置新的hostname与shell A做区分 # hostname shell-B # hostnameshell-B #查看之前的ipc message queue # ipcs -q ------ Message Queues --------key msqid owner perms used-bytes messages #查看当前bash进程的PID# echo $$30372 切换回shell A <-----

#创建一对网卡，分别命名为veth0_11/veth1_11# ip link add veth0_11 type veth peer name veth1_11 #查看已经创建的网卡#ip a1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00    inet 127.0.0.1/8 scope host lo       valid_lft forever preferred_lft forever2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000    link/ether 5e:75:97:0d:54:17 brd ff:ff:ff:ff:ff:ff    inet 192.168.1.1/24 brd 192.168.1.255 scope global eth0       valid_lft forever preferred_lft forever3: br1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN qlen 1000    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff    inet 172.18.0.1/24 scope global br1       valid_lft forever preferred_lft forever96: veth1_11@veth0_11: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN qlen 1000    link/ether 5e:75:97:0d:54:0e brd ff:ff:ff:ff:ff:ff97: veth0_11@veth1_11: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN qlen 1000    link/ether a6:c7:1f:79:a6:a6 brd ff:ff:ff:ff:ff:ff #使用ip netns创建两个net namespace# ip netns add r1# ip netns add r2# ip netns listr2r1 (id: 0) #将两个网卡分别加入到对应的netns中# ip link set veth0_11 netns r1# ip link set veth1_11 netns r2#再次查看网卡，在bash当前的namespace中已经看不到veth0_11和veth1_11了# ip a1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00    inet 127.0.0.1/8 scope host lo       valid_lft forever preferred_lft forever2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000    link/ether 5e:75:97:0d:54:17 brd ff:ff:ff:ff:ff:ff    inet 192.168.1.1/24 brd 192.168.1.255 scope global eth0       valid_lft forever preferred_lft forever3: br1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN qlen 1000    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff    inet 172.18.0.1/24 scope global br1       valid_lft forever preferred_lft forever #接下来我们切换到对应的netns中对网卡进行配置#通过nsenter --net可以切换到对应的netns中，ip a展示了我们上面加入到r1中的网卡# nsenter --net=/var/run/netns/r1 /bin/bash# ip a1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN qlen 1    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:0097: veth0_11@if96: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000    link/ether a6:c7:1f:79:a6:a6 brd ff:ff:ff:ff:ff:ff link-netnsid 1 #对网卡配置ip并启动# ip addr add 172.18.0.11/24 dev veth0_11# ip link set veth0_11 up# ip a1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN qlen 1    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:0097: veth0_11@if96: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state LOWERLAYERDOWN qlen 1000    link/ether a6:c7:1f:79:a6:a6 brd ff:ff:ff:ff:ff:ff link-netnsid 1    inet 172.18.0.11/24 scope global veth0_11       valid_lft forever preferred_lft forever -----> 切换至shell B执行------------------------------------------------------------------ #在r1中ping veth1_11# ping 172.18.0.12PING 172.18.0.12 (172.18.0.12) 56(84) bytes of data.64 bytes from 172.18.0.12: icmp_seq=1 ttl=64 time=0.033 ms64 bytes from 172.18.0.12: icmp_seq=2 ttl=64 time=0.049 ms...#至此我们通过netns完成了创建net Namespace的小实验

#在shell B中我们同样切换到netns r2中进行配置#通过nsenter --net可以切换到r2，ip a展示了我们上面加入到r2中的网卡# nsenter --net=/var/run/netns/r2 /bin/bash#  ip a1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN qlen 1    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:0096: veth1_11@if97: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000    link/ether 5e:75:97:0d:54:0e brd ff:ff:ff:ff:ff:ff link-netnsid 0 #对网卡配置ip并启动# ip addr add 172.18.0.12/24 dev veth1_11# ip link set veth1_11 up# ip a1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN qlen 1    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:0096: veth1_11@if97: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000    link/ether 5e:75:97:0d:54:0e brd ff:ff:ff:ff:ff:ff link-netnsid 0    inet 172.18.0.12/24 scope global veth1_11       valid_lft forever preferred_lft forever    inet6 fe80::5c75:97ff:fe0d:540e/64 scope link       valid_lft forever preferred_lft forever #尝试ping r1中的网卡# ping 172.18.0.11PING 172.18.0.11 (172.18.0.11) 56(84) bytes of data.64 bytes from 172.18.0.11: icmp_seq=1 ttl=64 time=0.046 ms64 bytes from 172.18.0.11: icmp_seq=2 ttl=64 time=0.040 ms...#可以完成通信 切换至shell A执行 <-----

#通过/proc/cgroups查看当前系统支持哪些subsystem# cat /proc/cgroups#subsys_name    hierarchy       num_cgroups     enabledcpuset              11              1           1cpu                 4               67          1cpuacct             4               67          1memory              5               69          1devices             7               62          1freezer             8               1           1net_cls             6               1           1blkio               9               62          1perf_event          3               1           1hugetlb             2               1           1pids                10              62          1net_prio            6               1           1 #字段含义#subsys_name: subsystem的名称#hierarchy：subsystem所关联到的cgroup树的ID，如果多个subsystem关联到同一颗cgroup树，那么他们的这个字段将一样，比如这里的cpu和cpuacct就一样，表示他们绑定到了同一颗树。如果出现下面的情况，这个字段将为0：        当前subsystem没有和任何cgroup树绑定        当前subsystem已经和cgroup v2的树绑定        当前subsystem没有被内核开启#num_cgroups: subsystem所关联的cgroup树中进程组的个数，也即树上节点的个数#enabled: 1表示开启，0表示没有被开启(可以通过设置内核的启动参数“cgroup_disable”来控制subsystem的开启).

#查看当前shell进程所属的cgroup# cat /proc/$$/cgroup11:cpuset:/10:pids:/system.slice/sshd.service9:blkio:/system.slice/sshd.service8:freezer:/7:devices:/system.slice/sshd.service6:net_prio,net_cls:/5:memory:/system.slice/sshd.service4:cpuacct,cpu:/system.slice/sshd.service3:perf_event:/2:hugetlb:/1:name=systemd:/system.slice/sshd.service #字段含义(以冒号分为3列)：# 1. cgroup树ID，对应/proc/cgroups中的hierachy# 2. cgroup所绑定的subsystem,多个subsystem使用逗号分隔。name=systemd表示没有和任何subsystem绑定，只是给他起了个名字叫systemd。# 3. 进程在cgroup树中的路径，即进程所属的cgroup，这个路径是相对于挂载点的相对路径。

#过滤系统挂载可以查看cgroup# mount |grep cgrouptmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,mode=755)cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,xattr,release_agent=/usr/lib/systemd/systemd-cgroups-agent,name=systemd)cgroup on /sys/fs/cgroup/hugetlb type cgroup (rw,nosuid,nodev,noexec,relatime,hugetlb)cgroup on /sys/fs/cgroup/perf_event type cgroup (rw,nosuid,nodev,noexec,relatime,perf_event)cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpuacct,cpu)cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory)cgroup on /sys/fs/cgroup/net_cls,net_prio type cgroup (rw,nosuid,nodev,noexec,relatime,net_prio,net_cls)cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices)cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,freezer)cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio)cgroup on /sys/fs/cgroup/pids type cgroup (rw,nosuid,nodev,noexec,relatime,pids)cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset) #如果系统中没有挂载cgroup，可以使用mount命令创建cgroup#挂载根cgroup# mkdir /sys/fs/cgroup# mount -t tmpfs cgroup_root /sys/fs/cgroup #将cpuset subsystem关联到/sys/fs/cgroup/cpu_memory# mkdir /sys/fs/cgroup/cpuset# sudo mount -t cgroup cpuset -o cgroup /sys/fs/cgroup/cpuset/ #将cpu和memory subsystem关联到/sys/fs/cgroup/cpu_memory# mkdir /sys/fs/cgroup/cpu_memory# sudo mount -n -t cgroup -o cpu,memory cgroup /sys/fs/cgroup/cpu_memory

# Centos操作系统可以通过yum install cgroup-tools 来安装以下命令    cgcreate: 在层级中创建新cgroup。        用法: cgcreate [-h] [-t <tuid>:<tgid>] [-a <agid>:<auid>] [-f mode] [-d mode] [-s mode]                -g <controllers>:<path> [-g ...]        示例: cgcreate -g *:student -g devices:teacher //在所有的挂载hierarchy中创建student cgroup,在devices                hierarchy挂载点创建teacher cgroup             cgset: 设置指定cgroup(s)的参数        用法: cgset [-r <name=value>] <cgroup_path> ...        示例: cgset -r cpuset.cpus=0-1 student //将student cgroup的cpuset控制器中的cpus限制为0-1             cgexec: 在指定的cgroup中运行任务        用法: cgexec [-h] [-g <controllers>:<path>] [--sticky] command [arguments]        示例: cgexec -g cpu,memory:test1 ls -l //在cpu和memory控制器下的test1 cgroup中运行ls -l命令

# 创建所需的目录# mkdir upper lower merged work# echo "lower" > lower/in_lower.txt# echo "upper" > upper/in_upper.txt # 在lower和upper中都创建 in_both文件# echo "lower" > lower/in_both.txt# echo "upper" > upper/in_both.txt #查看下我们当前的目录及文件结构# tree ..|-- lower|   |-- in_both.txt|   `-- in_lower.txt|-- merged|-- upper|   |-- in_both.txt|   `-- in_upper.txt`-- work #使用mount命令将创建的目录联合挂载起来# mount -t overlay overlay -o lowerdir=lower,upperdir=upper,workdir=work merged #查看mount结果可以看到已经成功挂载了# mount |grep overlayoverlay on /data/overlay_demo/merged type overlay (rw,relatime,lowerdir=lower,upperdir=upper,workdir=work) #此时再查看文件目录结构# tree ..|-- lower|   |-- in_both.txt|   `-- in_lower.txt|-- merged|   |-- in_both.txt|   |-- in_lower.txt|   `-- in_upper.txt|-- upper|   |-- in_both.txt|   `-- in_upper.txt`-- work    `-- work#可以看到merged中包含了lower和upper中的文件#然后我查看merge中的in_both文件,验证了上层目录覆盖下层的结论# cat merged/in_both.txtupper #上面我们验证了挂载后overlayfs的读，接下来我们去验证下写#我们在merged中创建一个新文件，并查看# touch merged/new_file# tree ..|-- lower|   |-- in_both.txt|   `-- in_lower.txt|-- merged|   |-- in_both.txt|   |-- in_lower.txt|   |-- in_upper.txt|   `-- new_file|-- upper|   |-- in_both.txt|   |-- in_upper.txt|   `-- new_file`-- work    `-- work#可以看到新文件实际是放在了upper目录中 #下面我们看下如果删除了lower和upper中都有的文件会怎样# rm -f merged/in_both.txt# tree ..|-- lower|   |-- in_both.txt|   `-- in_lower.txt|-- merged|   |-- in_lower.txt|   |-- in_upper.txt|   `-- new_file|-- upper|   |-- in_both.txt|   |-- in_upper.txt|   `-- new_file`-- work    `-- work #从文件目录上看只有merge中没有了in_both文件，但是upper中的文件已经发生了变化# ll upper/in_both.txtc--------- 1 root root 0, 0 Jan 21 19:33 upper/in_both.txt#upper/in_both.txt已经变成了一个空的字符文件，且覆盖了lower层的内容

#!/usr/bin/env bashset -o errexit -o nounset -o pipefail; shopt -s nullgloboverlay_path='/var/lib/bocker/overlay' && container_path='/var/lib/bocker/containers' && cgroups='cpu,cpuacct,memory';[[ $# -gt 0 ]] && while [ "${1:0:2}" == '--' ]; do OPTION=${1:2}; [[ $OPTION =~ = ]] && declare "BOCKER_${OPTION/=*/}=${OPTION/*=/}" || declare "BOCKER_${OPTION}=x"; shift; done function bocker_check() {    case ${1:0:3} in        img) ls "$overlay_path" | grep -qw "$1" && echo 0 || echo 1;;        ps_) ls "$container_path" | grep -qw "$1" && echo 2 || echo 3;;    esac} function bocker_init() { #HELP Create an image from a directory:\nBOCKER init <directory>    uuid="img_$(shuf -i 42002-42254 -n 1)"    if [[ -d "$1" ]]; then        [[ "$(bocker_check "$uuid")" == 0 ]] && bocker_run "$@"        mkdir "$overlay_path/$uuid" > /dev/null        cp -rf --reflink=auto "$1"/* "$overlay_path/$uuid" > /dev/null        [[ ! -f "$overlay_path/$uuid"/img.source ]] && echo "$1" > "$overlay_path/$uuid"/img.source        [[ ! -d "$overlay_path/$uuid"/proc ]] && mkdir "$overlay_path/$uuid"/proc        echo "Created: $uuid"    else        echo "No directory named '$1' exists"    fi} function bocker_pull() { #HELP Pull an image from Docker Hub:\nBOCKER pull <name> <tag>    tmp_uuid="$(uuidgen)" && mkdir /tmp/"$tmp_uuid"    download-frozen-image-v2 /tmp/"$tmp_uuid" "$1:$2" > /dev/null    rm -rf /tmp/"$tmp_uuid"/repositories    for tar in $(jq '.[].Layers[]' --raw-output < /tmp/$tmp_uuid/manifest.json); do        tar xf /tmp/$tmp_uuid/$tar -C /tmp/$tmp_uuid && rm -rf /tmp/$tmp_uuid/$tar    done    for config in $(jq '.[].Config' --raw-output < /tmp/$tmp_uuid/manifest.json); do        rm -f /tmp/$tmp_uuid/$config    done    echo "$1:$2" > /tmp/$tmp_uuid/img.source    bocker_init /tmp/$tmp_uuid && rm -rf /tmp/$tmp_uuid} function bocker_rm() { #HELP Delete an image or container:\nBOCKER rm <image_id or container_id>    [[ "$(bocker_check "$1")" == 3 ]] && echo "No container named '$1' exists" && exit 1    [[ "$(bocker_check "$1")" == 1 ]] && echo "No image named '$1' exists" && exit 1    if [[ -d "$overlay_path/$1" ]];then        rm -rf "$overlay_path/$1" && echo "Removed: $1"    else        umount "$container_path/$1"/merged && rm -rf "$container_path/$1" && ip netns del netns_"$1" && ip link del dev veth0_"$1" && echo "Removed: $1"        cgdelete -g "$cgroups:/$1" &> /dev/null    fi     } function bocker_images() { #HELP List images:\nBOCKER images    echo -e "IMAGE_ID\t\tSOURCE"    for img in "$overlay_path"/img_*; do        img=$(basename "$img")        echo -e "$img\t\t$(cat "$overlay_path/$img/img.source")"    done} function bocker_ps() { #HELP List containers:\nBOCKER ps    echo -e "CONTAINER_ID\t\tCOMMAND"    for ps in "$container_path"/ps_*; do        ps=$(basename "$ps")        echo -e "$ps\t\t$(cat "$container_path/$ps/$ps.cmd")"    done} function bocker_run() { #HELP Create a container:\nBOCKER run <image_id> <command>    uuid="ps_$(shuf -i 42002-42254 -n 1)"    [[ "$(bocker_check "$1")" == 1 ]] && echo "No image named '$1' exists" && exit 1    [[ "$(bocker_check "$uuid")" == 2 ]] && echo "UUID conflict, retrying..." && bocker_run "$@" && return    cmd="${@:2}" && ip="$(echo "${uuid: -3}" | sed 's/0//g')" && mac="${uuid: -3:1}:${uuid: -2}"    ip link add dev veth0_"$uuid" type veth peer name veth1_"$uuid"    ip link set dev veth0_"$uuid" up    ip link set veth0_"$uuid" master br1    ip netns add netns_"$uuid"    ip link set veth1_"$uuid" netns netns_"$uuid"    ip netns exec netns_"$uuid" ip link set dev lo up    ip netns exec netns_"$uuid" ip link set veth1_"$uuid" address 02:42:ac:11:00"$mac"    ip netns exec netns_"$uuid" ip addr add 172.18.0."$ip"/24 dev veth1_"$uuid"    ip netns exec netns_"$uuid" ip link set dev veth1_"$uuid" up    ip netns exec netns_"$uuid" ip route add default via 172.18.0.1    mkdir -p "$container_path/$uuid"/{lower,upper,work,merged} && cp -rf --reflink=auto "$overlay_path/$1"/* "$container_path/$uuid"/lower > /dev/null && \    mount -t overlay overlay \        -o lowerdir="$container_path/$uuid"/lower,upperdir="$container_path/$uuid"/upper,workdir="$container_path/$uuid"/work \        "$container_path/$uuid"/merged    echo 'nameserver 114.114.114.114' > "$container_path/$uuid"/merged/etc/resolv.conf    echo "$cmd" > "$container_path/$uuid/$uuid.cmd"    cgcreate -g "$cgroups:/$uuid"    : "${BOCKER_CPU_SHARE:=512}" && cgset -r cpu.shares="$BOCKER_CPU_SHARE" "$uuid"    : "${BOCKER_MEM_LIMIT:=512}" && cgset -r memory.limit_in_bytes="$((BOCKER_MEM_LIMIT * 1000000))" "$uuid"    cgexec -g "$cgroups:$uuid" \        ip netns exec netns_"$uuid" \        unshare -fmuip --mount-proc \        chroot "$container_path/$uuid"/merged \        /bin/sh -c "/bin/mount -t proc proc /proc && $cmd" \        2>&1 | tee "$container_path/$uuid/$uuid.log" || true    ip link del dev veth0_"$uuid"    ip netns del netns_"$uuid"} function bocker_exec() { #HELP Execute a command in a running container:\nBOCKER exec <container_id> <command>    [[ "$(bocker_check "$1")" == 3 ]] && echo "No container named '$1' exists" && exit 1    cid="$(ps o ppid,pid | grep "^$(ps o pid,cmd | grep -E "^\ *[0-9]+ unshare.*$1" | awk '{print $1}')" | awk '{print $2}')"    [[ ! "$cid" =~ ^\ *[0-9]+$ ]] && echo "Container '$1' exists but is not running" && exit 1    nsenter -t "$cid" -m -u -i -n -p chroot "$container_path/$1"/merged "${@:2}"} function bocker_logs() { #HELP View logs from a container:\nBOCKER logs <container_id>    [[ "$(bocker_check "$1")" == 3 ]] && echo "No container named '$1' exists" && exit 1    cat "$container_path/$1/$1.log"} function bocker_commit() { #HELP Commit a container to an image:\nBOCKER commit <container_id> <image_id>    [[ "$(bocker_check "$1")" == 3 ]] && echo "No container named '$1' exists" && exit 1    [[ "$(bocker_check "$2")" == 0 ]] && echo "Image named '$2' exists" && exit 1    mkdir "$overlay_path/$2" && cp -rf --reflink=auto "$container_path/$1"/merged/* "$overlay_path/$2" && sed -i "s/:.*$/:$(date +%Y%m%d-%H%M%S)/g" "$overlay_path/$2"/img.source    echo "Created: $2"} function bocker_help() { #HELP Display this message:\nBOCKER help    sed -n "s/^.*#HELP\\s//p;" < "$1" | sed "s/\\\\n/\n\t/g;s/$/\n/;s!BOCKER!${1/!/\\!}!g"} [[ -z "${1-}" ]] && bocker_help "$0" && exit 1case $1 in    pull|init|rm|images|ps|run|exec|logs|commit) bocker_"$1" "${@:2}" ;;    *) bocker_help "$0" ;;esac