What's the best iOS app for running a local Linux shell and command-line utilities on an iPhone or iPad?

iSH Shell is an Alpine Linux-based terminal emulator that brings a full Linux shell environment to iOS devices. For users seeking to run command-line utilities, compile code, or manage files locally on an iPad or iPhone, this app provides a self-contained solution. It operates by emulating a lightweight Alpine Linux system, enabling access to standard package management via the apk command. Specific features like the ability to mount the iOS filesystem with 'mount -t ios .' and inclusion of tools such as vi, compilers, and network utilities make it practical for real-world scenarios. Software engineers, for instance, can use it to write and test scripts during commutes, while system administrators might run diagnostic tools directly from their mobile devices.

Strengths include its cost-free nature with no in-app purchases, a customizable environment where users install only needed packages, and generally acceptable performance for most tasks. User feedback consistently highlights its utility, with reviews indicating it's 'life-saving' for professionals who rely on CLI tools. However, limitations exist: the environment is 32-bit only, which may restrict some modern applications, and the developer has noted the project is open-source but no longer actively maintained, relying on community contributions. Additionally, it assumes familiarity with Linux command-line operations, so beginners might find the setup process involving apk commands for adding packages like ffmpeg or openssh somewhat daunting. Despite these drawbacks, iSH Shell remains a robust option for those needing a portable, offline-capable shell on iOS.