Shell Programming and Scripting

I am Application Administrator with little bit experience with UNIX , We are changing the OS from AIX to Red hat Linux . Wondering if there anyway how to change the scripts to work on LINUX env and how to start to modify the scripts..Any Suggestions

Thanks in Advance

A good general overview concerning commands and important files can be found here: Rosetta Stone for Unix

Concerning shell scripts, make sure that you specify the exact shell needed (eg. /usr/bin/ksh) instead of a general shell, and rewrite hard-coded paths to use either $PATH or script-specific variables that can easily be adapted.

If the paths of script interpreters have changed, you might just add symlinks for them. If a script interpreter is missing, see if you can install a compatible version.

Another thing to scan for is dynamic library path setting:

Shared Libraries
3.3.1. LD_LIBRARY_PATH

You can temporarily substitute a different library for this particular execution. In Linux, the environment variable LD_LIBRARY_PATH is a colon-separated set of directories where libraries should be searched for first, before the standard set of directories; this is useful when debugging a new library or using a nonstandard library for special purposes. The environment variable LD_PRELOAD lists shared libraries with functions that override the standard set, just as /etc/ld.so.preload does. These are implemented by the loader /lib/ld-linux.so. I should note that, while LD_LIBRARY_PATH works on many Unix-like systems, it doesn't work on all; for example, this functionality is available on HP-UX but as the environment variable SHLIB_PATH, and on AIX this functionality is through the variable LIBPATH (with the same syntax, a colon-separated list).

Thanks Pickeet and Pludi for the replies..I started tweaking the scripts and I am stuck with this , We have Main Script which inturns invokes the Child script and main script is failing to locate the child script specified in main script. This is the content of Main Script where its locating the child script and failing in Linux

AIX
#!/bin/ksh
. /apps/webroot/admin/websrc

LINUX
#!/bin/bash
. /apps/webroot/admin/websrc

'apps/webroot/admin/websrc: line 2: syntax error near unexpected token `in

Checked for any empty spaces or invalid characters which might have caused syntax error and found nothing

Also One more error

/apps/webroot/admin/websrc: line 71: typeset: -u: invalid option

In AIX its defined as

typeset -u ENV_DESC=${WEBSRC_ENV}

Please Suggest where am i doing wrong...

The error message pertains to line 2 of the sourced file /apps/webroot/admin/websrc not line 2 of the calling script.

instead of the ksh

Code:

typeset -u ENV_DESC=${WEBSRC_ENV}

you could try this bash expansion:

Code:

ENV_DESC=${WEBSRC_ENV}
echo "${ENV_DESC^^}"

Isn't typeset -u for conversion to upper case?

I would have thought this would have been closer:

Code:

ENV_DESC=$(echo ${WESRC_ENV} | tr [a-z] [A-Z])

Rather than convert all your scripts from ksh to bash, have you considered trying pdksh?

so you why not use ksh in Linux also and replace by bash?