Switch currently used gcc cross-compiler versions

gcc_cross_switch_version.sh

#!/bin/bash

# This script changes the `arm-linux-gnueabihf-*` (or specified prefix)
# symlinks in /usr/bin to point to the specified version
# e.g. running with "7" as the argument will create the symlink
# /usr/bin/arm-linux-gnueabihf-gcc -> /usr/bin/arm-linux-gnueabihf-gcc-7
# and so on for all the normal cross-compiler commands

CMDS=( "gcc" "gcc-ar" "gcc-nm" "gcc-ranlib" "cpp" "gcov" "gcov-dump" "gcov-tool" )
BINPATH=/usr/bin

set -e

if [ "$#" -lt "1" ] || [ "$#" -gt "2" ]; then
  echo "Usage: $0 <version_number> [prefix] " >&2
  echo "" >&2
  echo "  Where [prefix] is the binary prefix e.g. 'arm-linux-gnueabihf' (the default)" >&2
  echo "" >&2
  exit 1
fi

if [ "$EUID" -ne "0" ]
  then echo "This script must be run as root" >&2
  exit 1
fi

cd $BINPATH

# First argument is version number
VERSION=$1

# Second (optional) argument is binary prefix
if [ ! -z "$2" ]; then
  PREFIX="${2}-"
else
  PREFIX="arm-linux-gnueabihf-"
fi

function do_symlink {
  ACTUALLY_SYMLINK=$1
  if [ ! -z $ACTUALLY_SYMLINK ]; then
    echo "Symlinking:"
  fi
  
  for CMD in "${CMDS[@]}"
  do
    SYMPATH="${PREFIX}$CMD"
    CMDPATH="${SYMPATH}-$VERSION"
  
    if [ ! -f $CMDPATH ]; then
      echo "File does not exist: $CMDPATH" >&2
      exit 1
    fi

    if [ ! -z $ACTUALLY_SYMLINK ]; then
      echo "${BINPATH}/$SYMPATH -> ${BINPATH}/$CMDPATH"
      rm -f $SYMPATH
      ln -s $CMDPATH $SYMPATH
    fi
  done
}

do_symlink
do_symlink 1