How to Run Shell Scripts from Apache Ant (and Set Unix File Permissions Safely)

This guide explains how to combine Apache Ant with Unix shell scripts for build tasks such as setting file permissions and processing files. It is aimed at engineers maintaining legacy Ant-based automation who need reliable, repeatable behavior in CI/CD environments.

Originally published on 2009-06-20; fully revised and updated.

Original post for reference: Ant Script with Shell script, How to run shell script from Ant Script?.

What this Ant + shell integration typically solves

• Set execute permissions on scripts before running them.
• Call shell utilities that are not available as native Ant tasks.
• Run file cleanup or text normalization during builds.

Choose the right approach: native Ant task vs shell execution

Prefer native Ant tasks when they exist, and use shell commands through exec when you need OS-specific tooling.

Execution flow when Ant runs shell commands

flowchart TD
    A[Ant target starts] --> B{Native Ant task available}
    B -- Yes --> C[Run built in Ant task]
    B -- No --> D[Use exec task]
    D --> E[Call shell script with args]
    E --> F[Script returns exit code]
    F --> G{Exit code is zero}
    G -- Yes --> H[Continue build]
    G -- No --> I[Fail build when failonerror is true]

Set file permissions directly in Ant

Use Ant’s chmod task to ensure scripts are executable before calling them.

<project name="example" default="fix-perms" basedir=".">
  <target name="fix-perms">
    <chmod perm="755">
      <fileset dir="${basedir}/scripts">
        <include name="**/*.sh"/>
      </fileset>
    </chmod>
  </target>
</project>Code language: HTML, XML (xml)

Run a shell script from Ant

Call a script file (recommended)

<target name="run-cleanup" depends="fix-perms">
  <exec executable="/bin/sh" failonerror="true">
    <arg value="${basedir}/scripts/cleanup-crlf.sh"/>
    <arg value="${basedir}/input"/>
  </exec>
</target>Code language: HTML, XML (xml)

Run a one-liner inline

<target name="list-text-files">
  <exec executable="/bin/sh" failonerror="true">
    <arg value="-c"/>
    <arg value="find '${basedir}/input' -type f -name '*.txt' -print"/>
  </exec>
</target>Code language: HTML, XML (xml)

Example cleanup script for carriage-return removal

The original post referenced removing special characters. The script below shows a safer pattern for removing carriage returns from text files and replacing files atomically.

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

root_dir="${1:-.}"

find "$root_dir" -type f -print0 | while IFS= read -r -d '' file; do
  tmp="${file}.tmp"
  tr -d '\r' < "$file" > "$tmp"
  mv "$tmp" "$file"
  echo "updated: $file"
doneCode language: PHP (php)

chmod +x scripts/cleanup-crlf.sh
ant run-cleanup

Best practices

• Use failonerror="true" so shell failures stop the build immediately.
• Keep complex shell logic in versioned .sh files, not inline command strings.
• Apply cleanup only to known text files to avoid corrupting binaries.
• Use Ant properties for paths instead of hardcoding directories.
• Validate shell availability (/bin/sh or bash) on each CI runner image.

Rajesh Kumar

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.

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