[linux] How does "cat << EOF" work in bash?

Using tee instead of cat

Not exactly as an answer to the original question, but I wanted to share this anyway: I had the need to create a config file in a directory that required root rights.

The following does not work for that case:

$ sudo cat <<EOF >/etc/somedir/foo.conf
# my config file
foo=bar
EOF

because the redirection is handled outside of the sudo context.

I ended up using this instead:

$ sudo tee <<EOF /etc/somedir/foo.conf >/dev/null
# my config file
foo=bar
EOF

Examples related to linux

grep's at sign caught as whitespace How to prevent Google Colab from disconnecting? "E: Unable to locate package python-pip" on Ubuntu 18.04 How to upgrade Python version to 3.7? Install Qt on Ubuntu Get first line of a shell command's output Cannot connect to the Docker daemon at unix:/var/run/docker.sock. Is the docker daemon running? Run bash command on jenkins pipeline How to uninstall an older PHP version from centOS7 How to update-alternatives to Python 3 without breaking apt?

Examples related to bash

Comparing a variable with a string python not working when redirecting from bash script Zipping a file in bash fails How do I prevent Conda from activating the base environment by default? Get first line of a shell command's output Fixing a systemd service 203/EXEC failure (no such file or directory) /bin/sh: apt-get: not found VSCode Change Default Terminal Run bash command on jenkins pipeline How to check if the docker engine and a docker container are running? How to switch Python versions in Terminal?

Examples related to scripting

What does `set -x` do? Creating an array from a text file in Bash Windows batch - concatenate multiple text files into one Raise error in a Bash script How do I assign a null value to a variable in PowerShell? Difference between ${} and $() in Bash Using a batch to copy from network drive to C: or D: drive Check if a string matches a regex in Bash script How to run a script at a certain time on Linux? How to make an "alias" for a long path?

Examples related to heredoc

How to cat <<EOF >> a file containing code? here-document gives 'unexpected end of file' error What is the advantage of using heredoc in PHP? Using variables inside a bash heredoc How can I write a heredoc to a file in Bash script? How does "cat << EOF" work in bash? Executing multi-line statements in the one-line command-line? How to assign a heredoc value to a variable in Bash? Creating multiline strings in JavaScript