[ale] Pi - how to change /usr/local/bin when / is RO?

[neal at mnopltd.com]

Wow.  that's like, magic.   Yes, apparently.

I was thinking you'd have to unmount, and then the world goes away.



On 2020-11-22 07:35, Leam Hall via Ale wrote:
> Hey Neal, I'm not an RPi guy, but would a remount work?
> 
> 	mount -o remount,rw /
> 
> Leam
> 
> On 11/22/20 8:27 AM, Neal Rhodes via Ale wrote:
>> I'm betting there is a way to do this.
>> 
>> JackTrip Virtual Studio runs on a Pi 3B.
>> 
>> Their init script needs to change to enable microphone bias voltage on 
>> startup.
>> 
>> amixer set 'ADC Mic Bias',0 'Mic Bias on'
>> 
>> In order for me to just hand this device to a musician and have them 
>> plug it in, I need to modify their init script in /usr/local/bin.
>> 
>> However, as you can see below, this is mounted read-only.
>> 
>> How does one get around this?
>> 
>> regards,
>> 
>> Neal
>> 
>> 
>> root at jacktrip:/usr/local/bin$ mount
>> /dev/mmcblk0p2 on / type ext4 (ro,noatime)
>> devtmpfs on /dev type devtmpfs 
>> (rw,relatime,size=440756k,nr_inodes=110189,mode=755)
>> sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
>> proc on /proc type proc (rw,relatime)
>> tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
>> devpts on /dev/pts type devpts 
>> (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
>> tmpfs on /run type tmpfs (rw,nosuid,nodev,mode=755)
>> tmpfs on /run/lock type tmpfs 
>> (rw,nosuid,nodev,noexec,relatime,size=5120k)
>> tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,mode=755)
>> cgroup2 on /sys/fs/cgroup/unified type cgroup2 
>> (rw,nosuid,nodev,noexec,relatime,nsdelegate)
>> cgroup on /sys/fs/cgroup/systemd type cgroup 
>> (rw,nosuid,nodev,noexec,relatime,xattr,name=systemd)
>> none on /sys/fs/bpf type bpf 
>> (rw,nosuid,nodev,noexec,relatime,mode=700)
>> 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/devices type cgroup 
>> (rw,nosuid,nodev,noexec,relatime,devices)
>> cgroup on /sys/fs/cgroup/net_cls type cgroup 
>> (rw,nosuid,nodev,noexec,relatime,net_cls)
>> cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup 
>> (rw,nosuid,nodev,noexec,relatime,cpu,cpuacct)
>> cgroup on /sys/fs/cgroup/freezer type cgroup 
>> (rw,nosuid,nodev,noexec,relatime,freezer)
>> cgroup on /sys/fs/cgroup/cpuset type cgroup 
>> (rw,nosuid,nodev,noexec,relatime,cpuset)
>> systemd-1 on /proc/sys/fs/binfmt_misc type autofs 
>> (rw,relatime,fd=29,pgrp=1,timeout=0,minproto=5,maxproto=5,direct)
>> mqueue on /dev/mqueue type mqueue (rw,relatime)
>> debugfs on /sys/kernel/debug type debugfs (rw,relatime)
>> configfs on /sys/kernel/config type configfs (rw,relatime)
>> tmpfs on /var/tmp type tmpfs (rw,nosuid,nodev,relatime)
>> tmpfs on /tmp type tmpfs (rw,nosuid,nodev,relatime)
>> tmpfs on /var/log type tmpfs (rw,nosuid,nodev,relatime)
>> /dev/mmcblk0p1 on /boot type vfat 
>> (ro,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,errors=remount-ro) 
>> tmpfs on /run/user/1000 type tmpfs 
>> (rw,nosuid,nodev,relatime,size=94804k,mode=700,uid=1000,gid=1000)
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