set -e causes the shell to exit if any subcommand or pipeline returns a non-zero status. The answer the interviewer was probably looking for is: It would be dangerous to use “set -e” when creating init.d scripts: From http://www.debian.org/doc/debian-policy/ch-opersys.html 9.3.2 — Be careful of using set -e in init.d scripts. Writing correct init.d scripts requires … Read more
You can press ctrl-z to interrupt the process and then run bg to make it run in the background. You can show a numbered list all processes backgrounded in this manner with jobs. Then you can run disown %1 (replace 1 with the process number output by jobs) to detach the process from the terminal. … Read more
For system-wide use, OpenSSL should provide you /etc/ssl/certs and /etc/ssl/private. The latter of which will be restricted 700 to root:root. If you have an application that doesn’t perform initial privilege separation from root, then it might suit you to locate them somewhere local to the application with the relevantly restricted ownership and permissions.
That depends on your distribution. On some system, it’s deleted only when booted, others have cronjobs running deleting items older than n hours. On Ubuntu 14: using tmpreaper which gets called by /etc/cron.daily, configured via /etc/default/rcS and /etc/tmpreaper.conf. (Credits to this answer). On Ubuntu 16: using tmpfiles.d. (Credits to this answer). On other Debian-like systems: … Read more
I’m sure someone else has a better answer, but With “less” after you’ve opened the file: G goes to the bottom of the file ^b goes up one page ? searches backwards. As you said, you can open the file with +G and then use ? and ^b to scroll up. There are likely clever … Read more
The mount command accepts –bind or -o bind. In the /etc/fstab file, you can use the following line: /source /destination none defaults,bind 0 0
I have written a dns proxy in Python. It will read wildcard entries in /etc/hosts. See here: https://github.com/hubdotcom/marlon-tools/blob/master/tools/dnsproxy/dnsproxy.py
cat /proc/<pid>/environ If you want to have pid(s) of a given running executable you can, among a number of other possibilities, use pidof: AlberT$ pidof sshd 30690 6512 EDIT: I totally quote Dennis Williamson and Teddy comments to achieve a more readable output. My solution is the following: tr ‘\0’ ‘\n’ < /proc/<pid>/environ
If you’re using Bash, you can run disown -h job disown disown [-ar] [-h] [jobspec …] Without options, each jobspec is removed from the table of active jobs. If the -h option is given, the job is not removed from the table, but is marked so that SIGHUP is not sent to the job if … Read more
I would use rsync as it means that if it is interrupted for any reason, then you can restart it easily with very little cost. And being rsync, it can even restart part way through a large file. As others mention, it can exclude files easily. The simplest way to preserve most things is to … Read more