How can I test for POSIX compliance of shell scripts?
Bash will run in POSIX-compliant mode if the POSIXLY_CORRECT environment variable is set. From the manpage: POSIXLY_CORRECT If this variable is in the environment when bash starts, the shell enters posix mode before reading the startup files, as if the –posix invocation option had been supplied.
Are there any shells that are compatible with POSIX?
As a second step, you can use a shell that is as compatible with POSIX as possible. One shell that is compatible with most other simple shells, is dash, Debian default system shell, which is a derivative of the older BSD ash. Another shell compatible with posix is posh.
How to make Bash conform to the POSIX standard?
Starting Bash with the –posix command-line option or executing ‘set -o posix’ while Bash is running will cause Bash to conform more closely to the POSIX standard by changing the behavior to match that specified by POSIX in areas where the Bash default differs. Thanks for contributing an answer to Stack Overflow!
Which is better lksh or mksh for POSIX?
Note that it’s strongly recommended to invoke lksh with at least the -o posix option, if not both that and -o sh, to fully enjoy better compatibility to the POSIX standard (which is probably why you use lksh over mksh in the first place) or legacy scripts, respectively. You would call lksh -o posix -o sh instead of the simple lksh.
How to get a password from a shell script without Bash?
A POSIX compliant answer. Notice the use of /bin/sh instead of /bin/bash. (It does work with bash, but it does not require bash.) Under Linux (and cygwin) this form works in bash and sh. It may not be standard Unix sh, though.
When to use ” equal to ” in POSIX shell?
Use these to check if a variable is empty or non-empty. If the length of string is non-zero. If the length of string is zero. Equal to. Not equal to. Note: Use == instead of = inside of [ [ for bash, zsh scripts. Equal to. Not equal to. Greater than. Greater than or equal to. Less than. Less than or equal to.