Building OpenWRT

 Compile OpenWRT Locally

If you're following the commands here https://openwrt.org/docs/guide-developer/build-system/use-buildsystem, specifically

# Download and update the sources
git clone https://git.openwrt.org/openwrt/openwrt.git openwrt
cd openwrt
git pull
 
# Select a specific code revision
git branch -a
git tag
git checkout v19.07.8
 
# Update the feeds
./scripts/feeds update -a
./scripts/feeds install -a
 
# Configure the firmware image and the kernel
make menuconfig
make kernel_menuconfig
 
# Build the firmware image
make -j $(nproc) defconfig download clean world

And finding out that the ./scripts/update -a fails because the which dependency isn't found then the solution is to temporarily remove the which alias.

Which is a very common GNU utility that tells you where a certain command is (on the filesystem or as an alias). On my Linux installation the which command is wrapped within an alias. 

• Remove it temporarily in a number of ways: you can go to /etc/profile.d/ and rename the which2.sh (or which2.csh depending on which shell you're using) to something that does not end in .sh. 
• Close the current terminal/session
• Start a new terminal and run which which and verify that you're getting the path of the which utility and not the alias
• Re-run the build steps
• Restore the which alias