Help, please. Bash commands work in terminal, but not in script.

[North]

I am trying to write the names of some directories to a text file.
The directory structure is like this:

|_FINISHED
    |_2-1-12-605pm
       |_2897-COOPER-ROAD-OTSEGO-MI-12345_PROPROPERTY_020112
       |_452-E-TEMPLE-AVE-KALAMAZOO-MI-49004_MACKYLTD_020112
       |_9098-BAILEY-HOPKINS-MI-49328_AMNRENTALS_020112
       |_123-OAK-ST-WAYLAND-MI-24680_PROPROPERTY_020112

So with these two commands, entered individually:

name=`find -maxdepth 2 -mindepth 2 -type d -printf '%P\n'`
echo "${name//\//-}">done.txt

The output to done.txt is:

2-1-12-605pm-2897-COOPER-ROAD-OTSEGO-MI-12345_PROPROPERTY_020112
2-1-12-605pm-452-E-TEMPLE-AVE-KALAMAZOO-MI-49004_MACKYLTD_020112
2-1-12-605pm-9098-BAILEY-HOPKINS-MI-49328_AMNRENTALS_020112
2-1-12-605pm-123-OAK-ST-WAYLAND-MI-24680_PROPROPERTY_020112

That is EXACTLY what I want.

BUT.... if I write it as a script like this:

#!/bin/sh -l

name=`find -maxdepth 2 -mindepth 2 -type d -printf '%P\n'`
echo "${name//\//-}">done.txt

It fails.

My output to the terminal is this:

./listfinished: 4: Bad substitution

What am I missing here?
If I write the script without the substitution, it works fine, albeit not really formatted like I would like.

[Cabhan]

I suspect that the problem is that the shebang line of your script is executing /bin/sh. You probably use /bin/bash for your shell.

When you execute /bin/sh, even though it's often the same program as bash, it runs a shell with fewer features:

       If bash is invoked with the name sh, it tries to mimic the startup behavior of  histori‐
       cal  versions  of  sh  as closely as possible, while conforming to the POSIX standard as
       well.  When invoked as an interactive login shell, or a non-interactive shell  with  the
       --login  option,  it  first  attempts to read and execute commands from /etc/profile and
       ~/.profile, in that order.  The --noprofile option may be used to inhibit this behavior.
       When  invoked as an interactive shell with the name sh, bash looks for the variable ENV,
       expands its value if it is defined, and uses the expanded value as the name of a file to
       read and execute.  Since a shell invoked as sh does not attempt to read and execute com‐
       mands from any other startup files, the --rcfile option has no effect.   A  non-interac‐
       tive  shell  invoked  with the name sh does not attempt to read any other startup files.
       When invoked as sh, bash enters posix mode after the startup files are read.

Try using /bin/bash in the shebang line and see if that works.

[North]

What the crap.

That was it. I never new that. Thanks for that. Alot.

Any reason I should ever use /bin/sh over /bin/bash?

[Irithori]

It may be, that there is no bash on a target system.
For example:
- A freebsd has sh and tcsh. bash would need to be installed.
- embedded devices also do not neccessarily have bash

So it depends on how portable you want your script to be.

btw:
Because bash is not in /bin/bash on e.g. freebsd, you could use this to gain some portability:

#!/usr/bin/env bash

[North]

That makes good sense.

Thank you both for the teachings.