Linux distributions sometimes configure “ll” (lowercase L’s) as an alias to “ls -l”. Debian based OS’s typically do this from the users ~/.bashrc file. This is not the case with Red Hat/CentOS based OS’s. I couldn’t remember where CentOS set the alias and I needed to locate it. As a non-root user, this proved to be a little more challenging than I first expected. Yes, I could look it up on the web but I decided to make an exercise out of it and it was more challenging than it would first seem.
grep -riE "alias ?ll" /etc/ 2> /dev/null
I’m sure there are other ways to it but this worked. In short. I knew I needed to search for “ll” in /etc, but “ll” is also common in many words. Also, I’m running as a normal user so I wanted to avoid “Permission Denied” and other errors that cluttered the search.
Note the the following also returns the same:
grep -riE "alias ?ll" /etc/ 2>&1 | grep -v "Permission"
It’s been a while since I last did this but you never know when you might need it. When you see a “dd” command, you better make sure you know what you are doing. In other words, don’t type this just as you see it!
Identify where CD/DVD is mounted:
Unmount the CD/DVD:
Copy data from CD/DVD to ISO file:
dd if/dev/sr0 of=~/image.iso
Or use dcfldd if you prefer:
dcfldd if/dev/sr0 of=~/image.iso
This is one of the oldest entries in my offline notes. I used it quite a bit years ago. Simply said, take several .pdf files and combine them into one file.
As always boys and girls – “man gs” in the terminal before you do this.*
gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=final.pdf file1.pdf file2.pdf file3.pdf
*As a side note: some of the options in the above command are not in the man page on my Debian 9 system. Man says you may need to install ghostscript-doc and view the pages in /usr/share/doc/ghostscript/
**Looks like “-o” is a shorthand to replace the “-dBATCH -dNOPAUSE” combination. https://www.ghostscript.com/doc/9.20/Use.htm