execline: a small scripting language

Software
skarnet.org

What is it?

execline is a (non-interactive) scripting language, like sh - but its syntax is quite different from a traditional shell syntax. The execlineb program is meant to be used as an interpreter for a text file; the other commands are essentially useful inside an execlineb script.

execline is as powerful as a shell: it features conditional loops, getopt-style option handling, filename globbing, and more. Meanwhile, its syntax is far more logical and predictable than the shell's syntax, and has no security issues.

• The execline design and grammar
• Why not just use /bin/sh?

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Installation

Requirements

• A POSIX-compliant system with a standard C development environment
• GNU make, version 3.81 or later.
• skalibs version 2.14.5.0 or later. It's a build-time requirement. It's also a run-time requirement if you link against the shared version of the skalibs library.

The following optional dependencies are also supported:

• If you're using musl and want nsswitch-like functionality: nsss version 0.2.1.1 or later (build-time and boot-time)

Licensing

execline is free software. It is available under the ISC license.

Download

• The current released version of execline is 2.9.8.0. You can access its checksum here.
• Alternatively, you can checkout a copy of the execline git repository:

   git clone git://git.skarnet.org/execline 

• There's also a GitHub mirror, or a SourceHut mirror of the execline git repository.

Compilation

• See the enclosed INSTALL file for installation details.
• Starting with 2.9.2.0, there's an --enable-multicall configure option to save disk space.

Upgrade notes

• This page lists the differences to be aware of between the previous versions of execline and the current one.

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Reference

Commands

All these commands exit 111 if they encounter a temporary error, and 100 if they encounter a permanent error - such as a misuse. They exit 127 if they're trying to execute into a program and cannot find it, and 126 if they fail to execute into a program for another reason.

(Script parser / launcher)

• The execlineb program

(Process state control)

• The execline-cd program
• The posix-cd program
• The execline-umask program
• The posix-umask program
• The emptyenv program
• The envfile program
• The export program
• The export-array program
• The unexport program
• The fdclose program
• The fdblock program
• The fdmove program
• The fdswap program
• The fdreserve program
• The redirfd program
• The piperw program
• The heredoc program
• The wait program
• The getcwd program
• The getpid program
• The exec program
• The tryexec program
• The exit program
• The trap program
• The withstdinas program

(Basic block management)

• The foreground program
• The background program
• The case program
• The if program
• The ifelse program
• The ifte program
• The ifthenelse program
• The backtick program
• The pipeline program
• The runblock program

(Variable management)

• The define program
• The importas program
• The elglob program
• The elgetpositionals program
• The multidefine program
• The multisubstitute program

(Loops)

• The forx program
• The forstdin program
• The forbacktickx program
• The loopwhilex program

(Positional parameters and options management)

• The elgetopt program
• The shift program
• The dollarat program

(Miscellaneous)

• The eltest program
• The homeof program

(Multicall configuration)

• The execline multicall binary

Provided scripts: example .profile replacement

• The execline-shell script
• The execline-startup script

Fun stuff

• An execline quine. This was quinely provided by Joël Riou. The only external command used is echo.
• Another quine, provided by Paul Jarc. It is much shorter, but uses the external commands echo and env. Later, Paul rewrote it using only echo, then using only echo and the environment.
• Another quine, provided by David Madore. It uses the external command printf. It is longer, but quite stylish.
• Another quine, provided by Sertonix. This one only uses commands from the execline package, and no external commands!

Related resources

execline manual pages

• flexibeast is providing the execline documentation as a set of man pages.

execline discussion

• execline is discussed on the skaware mailing-list.