Hi ,

I am trying to run a program in my linux machine which links to many shell scripts. Most of them have the first line as "#!/bin/sh -h". When I run the program I get the following error:
/bin/sh: 0: Illegal option -h

what kind of shell should I use ?

Hi,

I can think of three options:

1. Change your /bin/sh to link to something that understands -h
2. Change the shebang line in the scripts to something that understands -h
3. Modify the scripts to remove the -h

Evo2.

PS. "something that understands -h" is probably /bin/bash

Hi evo2,

Thanks for your reply. Even I thought about the same, but is there a way for updating all the scripts automatically. Is there some kind of find and replace utility available? Other than that could you mind explaining your first step and how do I achieve that?

Thanks,
Sanatan

Try the sed tool http://www.grymoire.com/Unix/Sed.html#uh-0 ; you may need to use 'find' to find the scripts unless you already know their locations.

Hi,

See Chris' post.

First you should check what /bin/sh actually points to. EG: on my system:
So I can see that /bin/sh is actually /bin/dash

To change it to /bin/bash you can do something like;
this needs to be done as root.

BEWARE: this means there will be a few seconds where you do not have any /bin/sh so in priciple it is best to do this in single user mode etc... if you screw this up it can leave your system in a state without /bin/sh, which would leave your system broken.
Also be aware that some scripts on your system may actually rely on "features" of whatever /bin/sh currently points to. "dashisms" have actually been found in the wild.
YOU BEEN WARNED.

Evo2.

Sorry about the allcaps yelling, but I just want to make it very clear that you should be very careful if you choose to do this.

Thankyou chris and Evo2 for your reply's . I managed to change the string in those script files with the following command:

and it works.

-Sanatan

In case it isn't perfectly clear, /bin/sh is the system's default POSIX shell. This can be provided by quite a few different actual shell interpreters, bash, ksh, zsh, dash, ash, and probably more. But what they all have in common is that when invoked as "#!/bin/sh", the script will be interpreted according to POSIX specifications. Some shells like dash and ash are in fact very strict posix-only shells and will not understand anything outside of what's defined there.

That's why you should always explicitly set your script's shebang to that of the actual interpreter you're writing for. If you're using bash, use #!/bin/bash, and nothing else.


Finally, I recommend not using evo2's suggestion for how to change the default shell. The distribution you're using undoubtedly has other, safer ways to do so. On Debian-based systems, for example, you should use "dpkg-reconfigure <shellname>". I also recommend configure-debian, the ncurses front-end for modifying such system parameters.

http://wiki.debian.org/DashAsBinSh
https://wiki.ubuntu.com/DashAsBinSh

Check your distro's documentation for their recommended way to do it.

1 members found this post helpful.

Hi,

Indeed, it was bad form on my part to suggest manually playing with the symlinks. It is far better to use the tools that your distro provides.

Cheers,

Evo2.