Linux Tips and Tricks

Introduction

Here is a collection of Linux commands that I find useful:
  • Search for all inp-files that contain the text “PENALTY” (case insensitive)
    grep --include=\*.inp -rnwli ~ -e "PENALTY"
  • List what hosts are active on the local network:
    arp-scan -l
    nmap -sn 192.168.86.0/24
  • Debugging a core dump:
    gdb executable core
    thread apply all bt
  • To determine if a Redhat / CentOS computer needs to be rebooted:
    sudo needs-restarting -r
  • Enable core dumps on Redhat / CentOS. As root type (needs to be done after each reboot):
    echo /tmp/core-%e-sig%s-user%u-group%g-pid%p-time%t > /proc/sys/kernel/core_pattern
  • Split and combine HUGE files:
    split --verbose -b1G file.tar file.tar.
    cat file.tar.* > file.tar
  • Update PolyUMod and MCalibration files (the \ before cp runs the command without any alias):
    cd PolyUMod_Installer_Lin64_vX.X.X/files
    \cp -r -p * /opt/PolymerFEM/
  • Run ANSYS in batch mode from a Windows PowerShell:
    C:/"Program Files"/"ANSYS Inc"/v192/ansys/bin/winx64/ANSYS192.exe -b -i simulation.dat -o job.output -j job -dis -np 1
  • Run LS-DYNA from a terminal:
    lsdyna i=file.k jobid=tmp
  • Create an animated gif-image from a set of png-images:
    convert -delay 150 -loop 0 *png myimage.gif
  • Setup vim so that only tabs with a width of 4 are used:
    set autoindent noexpandtab tabstop=4 shiftwidth=4
  • Take a screen shot of a region in Ubuntu 20.04:
    Ctrl + Shift + Print
  • Run a Windows installer in debug mode (I know, this is not for Linux, but still useful):
    msiexec /i Installer.msi /L*V C:\Temp\log.txt
  • When I tried to ANSYS v201 on Ubuntu 20.04 I got error like the following
    Syntax error: Bad fd number
    I was able to fix that odd error by editing the first line of the following 3 files:
    /opt/ansys_inc/v201/ansys/bin/ansysdis
    /opt/ansys_inc/v201/ansys/bin/mapdl
    /opt/ansys_inc/v201/ansys/bin/anssh.ini
    from
    #!/bin/sh
    to
    #!/bin/bash
    Now I can run the latest version of ANSYS on the latest version of Ubuntu. Cool.
  • Convert many 12-bit tif images to 16-bit images:
    for a in *tif; convert $a -depth 16 new_$a 
In the comments below, indicate what important (and “tricky”) commands that you would like to add!
Share on facebook
Facebook
Share on twitter
Twitter
Share on linkedin
LinkedIn

More to explore

Leave a Comment