until command
do
Statement(s) to be executed until command is true
doneCode language: JavaScript (javascript)Example
#!/bin/sh
a=0
until [ ! $a -lt 10 ]
do
echo $a
a=`expr $a + 1`
doneCode language: PHP (php)
I’m Rajesh Kumar, a DevOps, SRE, DevSecOps, Cloud, and Platform Engineering expert passionate about sharing practical knowledge, real-world experiences, and industry best practices. I have worked at Cotocus and regularly write about technology, travel, investing, health, product reviews, and digital marketing through my various platforms.
I publish technical articles at DevOps School, travel stories at Holiday Landmark, stock market insights at Stocks Mantra, health and fitness guidance at My Medic Plus, product reviews at TrueReviewNow, and SEO and digital marketing strategies at Wizbrand.
Find Trusted Cardiac Hospitals
Compare heart hospitals by city and services — all in one place.
Explore Hospitals
A practical angle that is often missing in shell scripting loop discussions is how
for,until, and other iteration constructs behave under real production workloads, especially in CI/CD pipelines and automation scripts running on shared or unstable infrastructure. In theory, loops are simple control structures, but in practice they become critical for handling bulk operations like deployments, log processing, batch file handling, and environment validation steps. One commonly overlooked issue is performance and safety—poorly designed loops can unintentionally create long-running processes, excessive API calls, or even resource exhaustion when operating on large datasets or cloud resources. Another real-world concern is error handling inside loops; if exit codes are not properly checked per iteration, a single failure may go unnoticed or, conversely, may stop the entire process prematurely depending onset -ebehavior. In production automation, it is also important to control retry logic, backoff strategies, and partial failure handling inside loops, which is often not emphasized in basic tutorials. Additionally, loops combined with external commands introduce variability due to network latency, filesystem state, or API rate limits, making observability and logging inside iterations essential for debugging. Ultimately, looping constructs are not just syntax features but core mechanisms that must be carefully engineered for reliability, scalability, and predictable behavior in real-world DevOps systems.