Re: [gentoo-user] Writing more complicated scripts than I'm used too.

[Frank Steinmetzger <Warp_7@gmx.de>]

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Am Tue, Jul 01, 2025 at 06:50:40PM -0500 schrieb Dale:

> OK.  I got one wrote, sort of.
> […]
> This is the script.  Tell me what I did wrong.  Please be kind.  This is
> the first real script I've ever done. 

I’ll share some of my bash wisdom. Some may be nitpicks, others a matter of 
personal taste.

> #/bin/bash
> 
> 
> # Define the mount point
> MOUNT_POINT="/home/dale/Desktop/Crypt"
> LVM_DEV="/dev/vg.crypt/crypt"
> 
> lsblk -o NAME -o LABEL | grep ^crypt-open > /dev/null
-------------------------------------------^^^^^^^^^^^^
grep has a -q option to suppress output, no redirection necessary.

> 
> if [ "$?" -eq "0" ] ; then
The `if $?` part is actually kinda nicely readable, but you could of course 
also do a direct `if lsblk | grep; then`.

>     echo "Crypt file system is open"
> 
>     else echo "Crypt is not open.  Please enter passphrase."
------^^^^^^^^^
Lol, it never occured to me that `else` may be followed by a command without 
semicolon, because I’ve always written it on its own line. It is however 
common practice to put the else on the same level of indentation as its 
respective `if` and `fi`.

>     cryptsetup open $LVM_DEV crypt
> fi


> 
> # Check if the disk is already mounted
> if mountpoint -q "$MOUNT_POINT"; then
>     echo "The disk is already mounted at $MOUNT_POINT."
>     # mount if not mounted
>     else mount $MOUNT_POINT
>     exit 0
> fi

Same thing here with the `else` indentation. It is not visible on first 
sight that there is an if/else/fi structure here. And it’s not immediately 
clear that the exit also belongs into the else block.


> This is simple still but hey, I'm new at this.  It does work on one part
> of it at least.  ROFL 

Tool tip: shellcheck. It will give all sorts of feedback on common pitfalls 
and give suggestions on improvements. For instance, it showed me something I 
overlooked (you wrote #/bin/bash instead of #!/bin/bash).

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