Installing programs on a removable drive

USB removable storage selector: USBKeyChooser

I think I have it:

Replacing grep -Hv 0 /sys/block/*/removable by grep -Hv ^ATA\ *$ /sys/block/*/device/vendor seem work:

export USBKEYS=($(
    grep -Hv ^ATA\ *$ /sys/block/*/device/vendor |
    sed s/device.vendor:.*$/device\\/uevent/ |
    xargs grep -H ^DRIVER=sd |
    sed s/device.uevent.*$/size/ |
    xargs grep -Hv ^0$ |
    cut -d / -f 4
))
for dev in ${USBKEYS[@]} ;do
    echo $dev \"$(
        sed -e s/\ *$//g </sys/block/$dev/device/model
        )\" ;
  done

Or even using readlink to ensure this is USB could be more accurate...

export USBKEYS=($(
    xargs -n1 readlink < <(echo /sys/block/*) |
    sed -ne 's+^.*/usb[0-9].*/\([^/]*\)$+/sys/block/\1/device/uevent+p' |
    xargs grep -H ^DRIVER=sd |
    sed s/device.uevent.*$/size/ |
    xargs grep -Hv ^0$ |
    cut -d / -f 4
))
for dev in ${USBKEYS[@]} ;do
    echo $dev \"$(
        sed -e s/\ *$//g </sys/block/$dev/device/model
        )\" ;
  done

Rewind:

In this I

1. Ensure this is USB (or removable

2. Ensure this work as an hard drive (not a CD-Rom)

3. Ensure they have size greater than 0 (not an empty Card reader)

Golfed version:

US=($(cut -d/ -f4 <(grep -vl ^0$ $(sed s@device/.*@size@ <(grep -l ^DRIVER=sd $(
  sed s+/device.*$+/dev*/ue*+ <(grep -Hv ^ATA\ *$ /sys/block/*/device/vendor)) <(:))) <(:))))

set | grep ^US=

This could be written

US=($(
    cut -d/ -f4 <(
        grep -vl ^0$ $(
            sed s@device/.*@size@ <(
                grep -l ^DRIVER=sd $(
                    sed -ne 's+^.*/usb[0-9].*/\([^/]*\)$+/sys/block/\1/dev*/ue*+p' <(
                        xargs -n1 readlink < <(echo /sys/block/*)
                    )
                ) /dev/null # equivalant but quicker than <(:)
            )) /dev/null)))

With readlink, golfed version become:

US=($(cut -d/ -f4 <(grep -vl ^0$ $(sed s@device/.*@size@ <(grep -l ^DRIVER=sd $(
    sed -ne 's+^.*/usb[0-9].*/\([^/]*\)$+/sys/block/\1/dev*/ue*+p' <(
    xargs -n1 readlink < <(echo /sys/block/*)) ) <(:))) <(:))))

In fine: usbKeyChooser

There is the final version of usbKeyChooser subroutine in my live installer:

#!/bin/bash
DIALOG=whiptail

usbKeyChoose() {
    while [ ! -b /dev/$STICK ] ;do
        USBKEYS=($(
                xargs -n1 readlink < <(echo /sys/block/*) |
                sed -ne 's+^.*/usb[0-9].*/\([^/]*\)$+/sys/block/\1/device/uevent+p' |
                xargs grep -H ^DRIVER=sd |
                sed s/device.uevent.*$/size/ |
                xargs grep -Hv ^0$ |
                cut -d / -f 4                 ))
        if [ ${#USBKEYS[@]} -eq 0 ];then
            title="No key found"
        else
            title="Choose wich USB stick have to be installed"
        fi

        menu=(R "Re scan devices")
        for dev in ${USBKEYS[@]} ;do
            read model </sys/block/$dev/device/model
            menu+=($dev "$model")
        done
        num=$($DIALOG --menu "$title" 21 72 14 "${menu[@]}" 2>&1 >/dev/tty)
        if [ ! "$num" ] ; then
            echo "User aborted."
            exit 0;
        fi
        [ ! "$num" = "R" ] && [ "${USBKEYS[num]}" ] && STICK=${USBKEYS[num]}
    done; }

usbKeyChoose
echo $STICK

I like this looping solution because they

• let insert many keys,
• wait for kernel registration,
• valid the choice,
• default to nothing and
• permit user abort.

Anyway, even if user did wrong ok choice, next screen is another choice asking user for which image have to be written on key defaulting to create new image wich is a very long process where user could hit Ctrl+c

Yes, you can do that. It's more work than relying on a package manager — the main attraction of “portable” installations under Windows is not to have to fight the lack of a decent package manager.

You'll need to arrange for the programs to find their dependencies: data files, libraries, etc. Many programs support environment variables for that. Some check the directory where the binary is located, or relative directories like ../lib, for companion files

Install the software under some root directory. Create the usual category directories under that root: bin, lib, man, etc. To manage all the software, install each one independently and then use a program like Stow create a forest of symbolic links to link them to the category directories. See Keeping track of programs for an introduction to Stow. You'll thus have symbolic links like

bin/foo -> ../stow/foo-1.42/bin/foo
bin/foobar -> ../stow/foo-1.42/bin/foobar
man/man1/foo.1 -> ../../stow/foo-1.42/man/man1/foo.1
…

You'll want a script to set up environment variables. Put it at the root of your installation and use $0 to locate the script. Since a script can't influence its parent, the usual approach is to make the script produce output that can be evaluated by the calling shell. Let's call this script setup.sh.

#!/bin/sh
set -e
root=$(dirname -- "$0")
cd -- "$root"
printf "PORTABLE_ROOT='%s'\\n" "${PWD}" | sed "s/'/'\\\\''/g"
prepend () {
  eval "set -- \"\$1\" \"\$2\" \"${$1}\""
  case :$3: in
    *:$PORTABLE_ROOT/$2:*) :;; # already there (at any location)
    :: echo '$1=$PORTABLE_ROOT/$2; export $1';; # the path was empty
    *) echo '$1=$PORTABLE_ROOT/$2:$3; export $1';; # prepend
  esac
}
prepend PATH bin
prepend MANPATH man
prepend LD_LIBRARY_PATH lib
prepend PERL5LIB lib/perl
prepend PYTHONPATH lib/python
…

(Warning: untested code)

To use the portable installation from a shell, run eval "`/path/to/setup.sh`".