Bash Read CSV Shell Script | while read & IFS

CSV imports power onboarding scripts, license lists, and one-off migrations. This template shows the safe while read pattern with IFS=',' — no accidental word-splitting on spaces — plus basic validation so bad rows do not stop the whole file.

What this script does

Skips the header row automatically
Trims whitespace around fields
Validates required columns and simple email format
Logs each accepted or skipped row with reason
Replace the process_row function with your business logic

Prerequisites

Bash on Linux
CSV with comma separator and no embedded commas in fields (or use proper CSV tooling)
Input file readable by the script user

Step 1: Save the script

sudo nano /usr/local/bin/import-users.sh
sudo chmod +x /usr/local/bin/import-users.sh

Step 2: Full script (scroll to read)

import-users.sh

#!/usr/bin/env bash
set -euo pipefail

CSV="${1:?usage: import-users.sh file.csv}"
LOG="/var/log/import-users.log"
ok=0; skip=0

log(){ echo "[$(date '+%F %T')] $*" | tee -a "$LOG"; }

valid_email(){ [[ "$1" =~ ^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}$ ]]; }

process_row(){
  local name="$1" email="$2"
  # TODO: useradd, API POST, etc.
  log "Row: $name,$email -> OK"
}

{
  read -r _header
  while IFS=',' read -r name email _rest; do
    name="${name#"${name%%[![:space:]]*}"}"; name="${name%"${name##*[![:space:]]}"}"
    email="${email#"${email%%[![:space:]]*}"}"; email="${email%"${email##*[![:space:]]}"}"
    if [[ -z "$name" || -z "$email" ]]; then
      log "SKIP invalid empty field: $name,$email"
      skip=$((skip+1)); continue
    fi
    if ! valid_email "$email"; then
      log "SKIP invalid email: $name,$email"
      skip=$((skip+1)); continue
    fi
    process_row "$name" "$email"
    ok=$((ok+1))
  done
} < "$CSV"

log "Import finished: ${ok} ok, ${skip} skipped"

Scroll inside the box to read the full script.

Step 3: Configure settings

For complex CSV (quoted commas), prefer python -c or csvkit
Example pairs with bulk user creation for real useradd calls
Always dry-run against a copy of production CSV first

Bash shell script reading CSV file line by line

Step 4: Test manually

echo 'name,email' > /tmp/users.csv

echo 'john,[email protected]' >> /tmp/users.csv

./import-users.sh /tmp/users.csv

Bash Read CSV File Line by Line Shell Script (IFS, Validation, Logging)