Yum Broken libelf.so libs* fix centos

  • Recently while installing letsencrypt I’ve come across yum being broken {by something @ somewhere} where yum tossed an error of libelf.so.1, a python shared object.

    Where yum nor rpm was able to run.

    So I ran ldconfig, which is a program used to maintain shared libraries. This from the man pages:

    • ldconfig creates the necessary links and cache to the most recent shared libraries found in the directories specified on the command line, in the file /etc/ld.so.conf, and in the trusted directories (/lib and /usr/lib). The cache is used by the run-time linker, ld.so or ld-linux.so.

    ldconfig checks the header and filenames of the libraries it encounters when determining which versions should have their links updated.

    So I got on with it using the -v flag or verbose

    ldconfig -v


    ldconfig: /etc/ld.so.conf.d/kernel-2.6.32-573.18.1.el6.x86_64.conf:6: duplicate hwcap 1 nosegneg
    ldconfig: /etc/ld.so.conf.d/kernel-2.6.32-573.22.1.el6.x86_64.conf:6: duplicate hwcap 1 nosegneg
    ldconfig: /etc/ld.so.conf.d/kernel-2.6.32-573.26.1.el6.x86_64.conf:6: duplicate hwcap 1 nosegneg
    ldconfig: /etc/ld.so.conf.d/kernel-2.6.32-573.7.1.el6.x86_64.conf:6: duplicate hwcap 1 nosegneg
    ldconfig: /etc/ld.so.conf.d/kernel-2.6.32-573.8.1.el6.x86_64.conf:6: duplicate hwcap 1 nosegneg
    ldconfig: /etc/ld.so.conf.d/kernel-2.6.32-642.1.1.el6.x86_64.conf:6: duplicate hwcap 1 nosegneg
    	libmysqlclient.so.16 -> libmysqlclient.so.16.0.0
    	libmysqlclient_r.so.16 -> libmysqlclient_r.so.16.0.0
    	libTix.so -> libTix.so
    	libbz2.so.1 -> libbz2.so.1.0.4
    	libSegFault.so -> libSegFault.so
    	libnsl.so.1 -> libnsl-2.12.so
    	libgssapi_krb5.so.2 -> libgssapi_krb5.so.2.2
    	libgmodule-2.0.so.0 -> libgmodule-2.0.so.0.2800.8
    	libkeyutils.so.1 -> libkeyutils.so.1.3
    	libncursesw.so.5 -> libncursesw.so.5.7
    	libfreeblpriv3.so -> libfreeblpriv3.so
    	libcrypt.so.1 -> libcrypt-2.12.so
    	libanl.so.1 -> libanl-2.12.so
    	libext2fs.so.2 -> libext2fs.so.2.4
    	libutil.so.1 -> libutil-2.12.so
    	libnss_nisplus.so.2 -> libnss_nisplus-2.12.so
    	libncurses.so.5 -> libncurses.so.5.7
    	libattr.so.1 -> libattr.so.1.1.0
    	libnss_hesiod.so.2 -> libnss_hesiod-2.12.so
    	libglib-2.0.so.0 -> libglib-2.0.so.0.2800.8
    	libz.so.1 -> libz.so.1.2.3
    	libselinux.so.1 -> libselinux.so.1
    	libkrb5.so.3 -> libkrb5.so.3.3
    	libdb-4.7.so -> libdb-4.7.so
    	libc.so.6 -> libc-2.12.so
    	libthread_db.so.1 -> libthread_db-1.0.so
    	libresolv.so.2 -> libresolv-2.12.so
    	libk5crypto.so.3 -> libk5crypto.so.3.1
    	libreadline.so.6 -> libreadline.so.6.0

    And so many other shared libraries…

    ldconfig in verbose mode will spit out shared libraries and links, re caching them.

    Once this is complete I ran:

    ldd /bin/rpm

    Which from the lunux man:

    • ldd prints the shared objects (shared libraries) required by each program or shared object specified on the command line.


    linux-vdso.so.1 =>  (0x00007fffaaeba000)
    	librpmbuild.so.1 => /usr/lib64/librpmbuild.so.1 (0x00007fa244e32000)
    	librpm.so.1 => /usr/lib64/librpm.so.1 (0x00007fa244bc7000)
    	libmagic.so.1 => /usr/lib64/libmagic.so.1 (0x00007fa2449a7000)
    	librpmio.so.1 => /usr/lib64/librpmio.so.1 (0x00007fa244778000)
    	libselinux.so.1 => /lib64/libselinux.so.1 (0x00007fa244559000)
    	libcap.so.2 => /lib64/libcap.so.2 (0x00007fa244354000)
    	libacl.so.1 => /lib64/libacl.so.1 (0x00007fa24414c000)
    	libdb-4.7.so => /lib64/libdb-4.7.so (0x00007fa243dd8000)
    	libbz2.so.1 => /lib64/libbz2.so.1 (0x00007fa243bc6000)
    	liblzma.so.0 => /usr/lib64/liblzma.so.0 (0x00007fa2439a5000)
    	liblua-5.1.so => /usr/lib64/liblua-5.1.so (0x00007fa243778000)
    	libm.so.6 => /lib64/libm.so.6 (0x00007fa2434f3000)
    	libelf.so.1 => /usr/lib64/libelf.so.1 (0x00007fa2432dd000)
    	libnss3.so => /usr/lib64/libnss3.so (0x00007fa242f9d000)
    	libpopt.so.0 => /lib64/libpopt.so.0 (0x00007fa242d93000)
    	libz.so.1 => /lib64/libz.so.1 (0x00007fa242b7d000)
    	librt.so.1 => /lib64/librt.so.1 (0x00007fa242975000)
    	libpthread.so.0 => /lib64/libpthread.so.0 (0x00007fa242757000)
    	libc.so.6 => /lib64/libc.so.6 (0x00007fa2423c3000)
    	libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007fa2421ac000)
    	libdl.so.2 => /lib64/libdl.so.2 (0x00007fa241fa8000)
    	/lib64/ld-linux-x86-64.so.2 (0x00007fa24506c000)
    	libattr.so.1 => /lib64/libattr.so.1 (0x00007fa241da3000)
    	libnssutil3.so => /usr/lib64/libnssutil3.so (0x00007fa241b76000)
    	libplc4.so => /lib64/libplc4.so (0x00007fa241971000)
    	libplds4.so => /lib64/libplds4.so (0x00007fa24176d000)
    	libnspr4.so => /lib64/libnspr4.so (0x00007fa24152e000)

    Boom, problem solved. Yum is functional again.

    As note, I cannot blame this on certbot, considering this system has been beaten down as a dev / trial. break & fix whatever was the flavor of the day for the last 3++ years. So this is by far the first issue I’ve caused by intentionally wreaking havok on a system. Comes with the territory.

Tmux Commands

screen and tmux

A comparison of the features (or more-so just a table of notes for accessing some of those features) for GNU screen and BSD-licensed tmux.

The formatting here is simple enough to understand (I would hope). ^ means ctrl+, so ^x is ctrl+x. M- means meta (generally left-alt or escape)+, so M-x is left-alt+x

It should be noted that this is no where near a full feature-set of either group. This - being a cheat-sheet - is just to point out the most very basic features to get you on the road.

Trust the developers and manpage writers more than me. This document is originally from 2009 when tmux was still new - since then both of these programs have had many updates and features added (not all of which have been dutifully noted here).

Action tmux screen
start a new session tmux OR
tmux new OR
tmux new-session
re-attach a detached session tmux attach OR
tmux attach-session
re-attach an attached session (detaching it from elsewhere) tmux attach -d OR
tmux attach-session -d
screen -dr
re-attach an attached session (keeping it attached elsewhere) tmux attach OR
tmux attach-session
screen -x
detach from currently attached session ^b d OR
^b :detach
^a ^d OR
^a :detach
rename-window to newname ^b , <newname> OR
^b :rename-window <newn>
^a A <newname>
list windows ^b w ^a w
list windows in chooseable menu ^a "
go to window # ^b # ^a #
go to last-active window ^b l ^a ^a
go to next window ^b n ^a n
go to previous window ^b p ^a p
see keybindings ^b ? ^a ?
list sessions ^b s OR
tmux ls OR
tmux list-sessions
screen -ls
toggle visual bell ^a ^g
create another window ^b c ^a c
exit current shell/window ^d ^d
split window/pane horizontally ^b " ^a S
split window/pane vertically ^b % ^a |
switch to other pane ^b o ^a <tab>
kill the current pane ^b x OR (logout/^D)
collapse the current pane/split (but leave processes running) ^a X
cycle location of panes ^b ^o
swap current pane with previous ^b {
swap current pane with next ^b }
show time ^b t
show numeric values of panes ^b q
toggle zoom-state of current pane (maximize/return current pane) ^b z
break the current pane out of its window (to form new window) ^b !
re-arrange current panels within same window (different layouts) ^b [space]
Kill the current window (and all panes within) ^b killw [target-window]
  • Mount NFS from Truenas

    mkdir -p /media/rick/pool1 chown -R rick:rick /media/rick/pool1

    Add the automount to: /etc/fstab

    truenas.thecave:/mnt/pool1 /media/rick/pool1 nfs user,auto 0 0

    Retstart Nautilus to see the share in files:

    killall nautilus

    For other shares, just repeat the same process under directory ‘media’ with the name of the share substituted

    read more
  • Again running smartctl after all is said and done:

    smartctl --all /dev/sda

    ddrescue-smartctl-after-rescue.png ddrescue-smartctl-2.png

    Yet an old drive in itself, I run the wheels off of them, and monitor regularly as anyone should.

    read more