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Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘Linux’ Category

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ls colour codes on OpenSuSE tumbleweed when accessed from Mac OS X ssh

Posted by jpluimers on 2019/06/07

`ls` colour codes

`ls` colour codes

I got confused as I thought red text would mean an error.

But they’re not: greenish yellow on a read background means error (a symbolic link to a place that’s no longer there).

It’s the output of https://github.com/gkotian/gautam_linux/blob/master/scripts/colours.sh as the one at

Actually the script is here https://raw.githubusercontent.com/gkotian/gautam_linux/master/scripts/colours.sh as the one at [WayBack] command line – What do the different colors mean in the terminal? – Ask Ubuntu failed with errors like this one:

-bash: *.xbm: bad substitution

The full script output is below.

Since various terminals have a different mapping from colours in the ANSI escape code colour table, I used the standard HTML colours using (which slightly differs from the Terminal.app screenshot on the right):

References:

Note that the shell on Mac OS X uses a different way of configuring colours CLICOLOR as described in [WayBack] settings – CLICOLOR and LS_COLORS in bash – Unix & Linux Stack Exchange. I might cover that another day.

Script output:

Read the rest of this entry »

Posted in *nix, *nix-tools, ANSI escape code, bash, CSS, Development, Encoding, HTML, HTML5, Linux, openSuSE, Power User, Software Development, SuSE Linux, Tumbleweed, Web Development | Leave a Comment »

When your btrfs partition is damaged.

Posted by jpluimers on 2019/05/27

A while ago, I somehow had a damaged btrfs partition that I found out after the virtualisation host without reason decided to reboot.

I’m not sure what caused that (by now the machine has been retired as it was already getting a bit old), but btrfs was panicking shortly after boot, so the VM as is was unusable.

In the end I had to:

  1. Boot from a Tumbleweed Rescue DVD (download Rescue CD – x86_64 from [WayBack] openSUSE:Tumbleweed installation – openSUSE)
  2. Add a fresh backup hard disk in read-write mote
  3. Mount the old one in read-only mode
  4. rsync -avloz over as much as I could
  5. Restore the VM from a backup
  6. Attach the backup hard disk
  7. Diff what I missed (only a few bits in the /etc tree and my home directory for which I hadn’t yet pushed the git repositories).

These didn’t work, but might work for others: [WayBack] SDB:BTRFS – openSUSE – How to repair a broken/unmountable btrfs filesystem

–jeroen

Posted in *nix, btrfs, File-Systems, Linux, openSuSE, Power User, SuSE Linux, Tumbleweed | Leave a Comment »

systemd – How to clear journalctl – Unix & Linux Stack Exchange

Posted by jpluimers on 2019/05/24

Some tips on pruning entries from the systemd journal:

For stock opensuse, this is also relevant, as it seems to allow indefinite growth: [WayBack] systemd – journald Settings likey need your attention

You can view disk usage with this command:

journalctl --disk-usage

–jeroen

Posted in *nix, Linux, Power User, systemd | Leave a Comment »

Reset Linux Desktop To Default Settings With A Single Command – OSTechNix

Posted by jpluimers on 2019/05/16

To reset Ubuntu Unity or any other Linux desktop with GNOME/MATE DEs to its default settings, run:

dconf reset -f /

Source: [WayBack] Reset Linux Desktop To Default Settings With A Single Command – OSTechNix

I need to check if it works on OpenSuSE with XFCE as there the dconf command is installed, but I still have a default desktop (mainly because most of the work I do is using a terminal over ssh).

–jeroen

via: [Archive.is] Never thought about dconf reset… Joe C. Hecht – Google+

Posted in *nix, *nix-tools, Linux, Power User, X11 | Leave a Comment »

command line – How to access a usb flash drive from the terminal? – Ask Ubuntu

Posted by jpluimers on 2019/05/13

Based on [WayBack] command line – How to access a usb flash drive from the terminal? – Ask Ubuntu

Figure out the device:

  • lsblk
  • sudo blkid
  • sudo fdisk -l

Mount the device (assuming it is /dev/sdb1):

  • sudo mount /dev/sdb1 /media/usb
  • pmount /dev/sdb1
  • udisksctl mount -b /dev/sdb1

Unmounting and eject is in [WayBack] Linux (Ubuntu): safely remove USB flash disk via command line – Stack Overflow

–jeroen

Posted in *nix, *nix-tools, Linux, Power User | Leave a Comment »

How to Find Out Top Directories and Files (Disk Space) in Linux

Posted by jpluimers on 2019/04/26

Cool list of ls , sort and find to get the largest files, directories: [WayBack] How to Find Out Top Directories and Files (Disk Space) in Linux.

–jeroen

Posted in *nix, *nix-tools, Linux, Power User | Leave a Comment »

OpenSuSE: multi-megabyte binary blob `/etc/udev/hwdb.bin` does not need to be versioned with `etckeeper` – via Unix & Linux Stack Exchange

Posted by jpluimers on 2019/04/22

I wondered [WayBack] linux – Why is this a binary multi-megabyte blob /etc/udev/hwdb.bin under /etc? – Unix & Linux Stack Exchange.

All my OpenSuSE systems had the /etc/udev/hwdb.bin file with sizes varying between 7.5 and 10 megabytes with many of the zypper dist-upgrade causing updates.

Luckily the system also contains these files which had valid unit definitions, so the file was generated/updated during boot:

  • /usr/bin/systemd-hwdb
  • /usr/lib/systemd/system/sysinit.target.wants/systemd-hwdb-up‌​date.service
  • /usr/lib/systemd/system/systemd-hwdb-update.service

Thanks [WayBack] nwildner for answering that question!

So after installing etckeeper and performing etckeeper init you can immediately remove it from the git repository:

# cd /etc
# git rm --cached /etc/udev/hwdb.bin
rm 'udev/hwdb.bin'
# git commit -m "no need for /etc/udev/hwdb.bin to be under revision control as systemd-hwdb maintains it"

For more background, see [WayBack] How to make Git “forget” about a file that was tracked but is now in .gitignore? – Stack Overflow.

–jeroen

 

Posted in *nix, *nix-tools, etckeeper, Linux, openSuSE, Power User, SuSE Linux, systemd, Tumbleweed | Leave a Comment »

Default OpenSuSE Postfix main.cf forgets to configure SASL for cyrus…

Posted by jpluimers on 2019/04/15

If you see the below in your Postfix log when trying to test your config, then the SASL configuration is empty. Oddly that seems the default on OpenSuSE for a while now, despite it providing cyrus SASL out of the box.

Sep 15 14:30:07 katrien postfix/smtpd[12719]: fatal: bad string length 0 < 1: smtpd_sasl_path =
Sep 15 14:30:08 katrien postfix/master[12400]: warning: process /usr/lib/postfix/smtpd pid 12719 exit status 1
Sep 15 14:30:08 katrien postfix/master[12400]: warning: /usr/lib/postfix/smtpd: bad command startup -- throttling

Prior OpenSuSE versions had this in /etc/postfix/main.cf:

# SASL stuff
############################################################
smtp_sasl_auth_enable = no
smtp_sasl_security_options =
smtp_sasl_password_maps =
smtpd_sasl_auth_enable = no
#smtpd_sasl_path = private/auth
#smtpd_sasl_type = dovecot

Newer OpenSuSE versions have this:

# SASL stuff
############################################################
smtp_sasl_auth_enable = no
smtp_sasl_security_options =
smtp_sasl_password_maps =
smtpd_sasl_auth_enable = no
# cyrus : smtpd_sasl_type = cyrus, smtpd_sasl_path = smtpd
# dovecot : smtpd_sasl_type = dovecot, smtpd_sasl_path = private/auth
smtpd_sasl_path =
smtpd_sasl_type = 

Despite the newer having these installed:

# rpm -qa | grep cyrus
cyrus-sasl-crammd5-2.1.26-14.2.aarch64
cyrus-sasl-2.1.26-14.2.aarch64
cyrus-sasl-plain-2.1.26-14.2.aarch64
cyrus-sasl-digestmd5-2.1.26-14.2.aarch64
cyrus-sasl-gssapi-2.1.26-14.2.aarch64

Solution:

smtpd_sasl_path = smtpd
smtpd_sasl_type = cyrus

Since the values for both lines are default, you could even comment them out; see the documentation:

–jeroen

Via: [WayBack] postfix IRC logs [July 26 – 2007]

Posted in *nix, *nix-tools, Linux, openSuSE, postfix, Power User, SuSE Linux, Tumbleweed | Leave a Comment »

crontab.guru – the cron schedule expression editor

Posted by jpluimers on 2019/04/12

Confused by crontab expressions? Me too, so I was happy to find: At minute 3 past every 12th hour: crontab.guru – the cron schedule expression editor.

It has a [WayBack] truckload of common crontab expressions, but more importantly allows you to live edit one, then explains in human terms what it means and when the schedule runs next.

If you like a step by step cron configurator, then you can try [WayBack] Cron Job Generator by GenerateIt.net but need to note it cannot interpret a cron expression.

–jeroen

Posted in *nix, *nix-tools, cron, Linux, Power User | Leave a Comment »

Some Postfix configuration guidelines

Posted by jpluimers on 2019/02/08

Not just for Postfix are the first two guidelines:

  • Change one thing at a time
  • Save known working configurations

For the latter, I’m using etckeeper pushing to an external git repository hoster.

For Postfix are the others from [WayBack] Postfix Configuration Guidelines.

One tip that’s missing, but saved my life numerous of times:

In /etc/postfix/main.cfg do not use this line ever:

inet_interfaces = $myhostname

If the resolving (through DNS or hosts file) of $myhostname fails for any reason in the future, then Postfix will not start at all, but in stead emit a fatal error like this:

/usr/sbin/postconf: fatal: parameter inet_interfaces: no local interface found for 127.0.0.2

Specify exact interfaces in stead, like any of these:

inet_interfaces = all

inet_interfaces = localhost

inet_interfaces = 192.168.24.68

–jeroen

Posted in *nix, *nix-tools, etckeeper, Linux, postfix, Power User | Leave a Comment »

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