Processing configuration files, server logs, or CSV data in Bash scripts requires reading text files line by line cleanly. The standard industry pattern uses a while IFS= read -r line loop with input redirection.

Standard Bash Line-by-Line Reading Template

read_file.shbash
#!/usr/bin/env bash
 
INPUT_FILE="servers.txt"
 
if [[ ! -f "${INPUT_FILE}" ]]; then
    echo "Error: File ${INPUT_FILE} not found." >&2
    exit 1
fi
 
# Read file line by line safely (IFS= preserves spaces, -r disables backslash escape)
while IFS= read -r line || [[ -n "${line}" ]]; do
    # Skip empty lines and comments starting with #
    [[ -z "${line}" || "${line}" =~ ^[[:space:]]*# ]] && continue
 
    echo "Processing Server Host: ${line}"
done < "${INPUT_FILE}"