[SOLVED] /etc/cron.hourly/somejob starts a bash script as dash

bai4Iej2need · 2024-10-17 12:21:56

I have tested now several versions
Version 1

head central_sync
#!/bin/bash
# synchronise Unlimited number of directories on different hosts
...

central_sync is a hardlink to /usr/local/bin/central_sync.bash

version 2

cat central_sync2
#!/bin/sh
set
/bin/bash /usr/local/bin/central_sync.bash

exit 0

version 3

cat central_sync3
#!/bin/sh
set
/bin/bash -x /usr/local/bin/central_sync.bash

exit 0

version 4

cat central_sync4
#!/bin/sh
set
/bin/bash --posix /usr/local/bin/central_sync.bash

exit 0

They all produce in the protocol log:

...
set 
...
SHELL=/bin/sh

Consequently the program fails, which runs when called in the console/terminal
Parameter expansion fails in the rsync command

Last edited by bai4Iej2need (2024-10-28 10:44:29)

OddS · 2024-10-19 09:28:12

I'm confused... perhaps because I don't know what "the protocol log" is or may be because you do not say if the log is produced when /etc/cron.hourly/somejob runs or when you start central_sync.bash manually

If I remember this correctly, cron does not know the environment you use in the terminal. That may explain the difference you observe, and possibly the parameter expansion problem.

Prove to yourself that /etc/cron.hourly/somejob is executable and that cron actually starts it. Study the output from set. Move on to locate what fails in /etc/cron.hourly/somejob

--
OddS

Last edited by OddS (2024-10-19 09:30:19)

bai4Iej2need · 2024-10-28 10:43:40

Hi
I failed to explain that I have a protocol function in the script which writes to /var/log/somejob/somejob.log, if executed as root.
I verified now that the script starts indeed as a dash script instead of starting as bash. Some command inside requires a bashism and then the script fails.
Works as root !
I correct now the headline as well.

Last edited by bai4Iej2need (2024-10-28 11:20:23)

bai4Iej2need · 2024-10-31 22:15:53

It is not possible to set the shell for a particular task in /etc/cron.hourly, etc/cron.daily, etc/cron.weekly and /etc/cron.monthly.
Setting shell for all jobs is in /etc/default/cron.
I moved the job into the crontab (crontab -e) of root.
Now we go to the next problem.

kaiyel · 2025-01-12 18:18:09

If your working environment relies heavily on bash, you might consider replacing DASH with BASH as the default shell as I did. It "just works" and I've had no cause to reconsider the decision :

HOWTO : use bash instead of dash as the default shell in daedalus
https://dev1galaxy.org/viewtopic.php?id=5753

Cheers,
--K

EDX-0 · 2025-01-13 05:30:54

another option is to use an inline script as a function with a heredoc.

here's an example of what is a posix compliant shell script that wraps the program nsxiv to add functionality but since there's no good way to decode a uri to a path with just the core utils a simple python script is used from a function, this sort of thing can be done with any interpreter for any language, say you want an awk script or a perl script, even a bash script the process would be all the same.

#!/bin/sh

TMPDIR="${TMPDIR:-/tmp}"
tmp="$TMPDIR/nsxiv_rifle_$$"

is_img_extension() {
    grep -iE '\.(jpe?g|png|gif|svg|jxl|webp|tiff|heif|avif|ico|bmp|pam|pbm|ppm|tga|qoi|ff|jpg_large)$'
}

listfiles() {
    if [ -n "$SORT_BY_TIME" ]; then
    find -L "$1" -maxdepth 1 -type f -printf '%T@\t%p\n' |
        sort -n | cut -f2 | is_img_extension | tee "$tmp"
    else
    find -L "$1" -maxdepth 1 -type f -print |
        is_img_extension | sort -Vfd | tee "$tmp"
    fi
}

open_img() {
    file="$1"; shift;
    # only go through listfiles() if the file has a valid img extension
    if echo "$file" | is_img_extension >/dev/null 2>&1; then
        trap 'rm -f $tmp' EXIT
        count="$(listfiles "///${file%/*}" | grep -nF "$file")"
    fi
    if [ -n "$count" ]; then
        nsxiv-env -i -n "${count%%:*}" "$@" -- < "$tmp"
    else
        # fallback incase file didn't have a valid extension, or we couldn't
        # find it inside the list
        nsxiv-env "$@" -- "$file"
    fi
}

uri2path() {
    python3 - "$@" <<'___HEREDOC'
from urllib.parse import unquote, urlparse
from sys import argv
for arg in argv[1:]:
    print(unquote(urlparse(arg).path))
___HEREDOC
}

[ "$1" = '--' ] && shift
case "$1" in
    "") echo "Usage: ${0##*/} PICTURES" >&2; exit 1 ;;
    /*) open_img "$1" ;;
    "~"/*) open_img "$HOME/${1#"~"/}" ;;
    file:///*) open_img "$(uri2path "$1")" ;;
    trash:///*)
        trash_dir="${XDG_DATA_HOME:-$HOME/.local/share}/Trash/files"
        open_img "${trash_dir}$(uri2path "$1")" -N "nsxiv_trash"
        ;;
    *) open_img "$PWD/$1" ;;
esac

another option is to have sub-scripts that may live in library paths, something like /usr/local/lib/mycronscript/module and then you run that module from inside your script as another executable.

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#1 2024-10-17 12:21:56

[SOLVED] /etc/cron.hourly/somejob starts a bash script as dash

#2 2024-10-19 09:28:12

Re: [SOLVED] /etc/cron.hourly/somejob starts a bash script as dash

#3 2024-10-28 10:43:40

Re: [SOLVED] /etc/cron.hourly/somejob starts a bash script as dash

#4 2024-10-31 22:15:53

Re: [SOLVED] /etc/cron.hourly/somejob starts a bash script as dash

#5 2025-01-12 18:18:09

Re: [SOLVED] /etc/cron.hourly/somejob starts a bash script as dash

#6 2025-01-13 05:30:54

Re: [SOLVED] /etc/cron.hourly/somejob starts a bash script as dash

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