Sometimes it’s necessary to create Linux user accounts in batch mode (fully automatic) but often newbies ask how to set password for a new user without entering it manually. Thanks to heaven command useradd can get password as an input parameter, but it should be… Read More »Create Linux user with password
Linux has an abundance of excellent terminal applications. Interestingly, I could not find any decent comparison of their text display performance. Since I use the command line a lot, I want text output that is as fast as possible. When you compile a large project,… Read More »Linux Terminal Performance Comparison
Unix and Linux GNU coreutils command paste can be useful to merge corresponding or subsequent lines of files. Here is simple example of it’s usage: viper@viper-laptop:~$ cat /tmp/test pop pop1 pop2 viper@viper-laptop:~$ cat /tmp/test1 1 2 3 4 viper@viper-laptop:~$ paste /tmp/test /tmp/test1 pop 1 pop1… Read More »Linux/Unix coreutils command ‘paste’ to merge lines of files
I found using of Unix time to be very useful in various shell scripts and here are two simple commands to convert Unix/Linux date command to Unix time format and back to regular formating: To convert Unix time to simple (regular) time please use: date… Read More »Two-way conversion of Unix time (seconds since 1970) and regular time
There are two commands that may help you to find where executable binary is located regardless it’s Unix or Linux system. They are whereis and type. First locates source/binary and manuals sections for specified files and second tells what exactly shell executes when you type… Read More »Find out where Unix/Linux executable binary is located
It sounds a bit cheesy but I can’t find any usable solution on how to encrypt Linux/Unix shell script in order to protect it’s source code when it’s still executable. There was a post here about how to protect shell scripts, but I found SHC… Read More »Can’t find usable shell script encryption solution…
Here is one more way to find out how many CPUs are used by Linux: cat /proc/cpuinfo | grep “^vendor_id” | wc -l As for me I use this way to make sure that SMP kernel should be installed. You’re welcome to suggest your ways… Read More »One more way to count CPUs in Linux
Here is a shell script example that can be run by cron for automatic killing of “zombie” processes in Linux system: zombies.sh
In order to change shell for a particular user of Unix/Linux system without editing /etc/passwd file manually just use command: chsh -s /path/to/shell username for example, to change shell to ‘sh’ from ‘bash’ for user ‘viper’, use command: chsh -s /bin/sh viper
I usually encrypt files with GPG with symmetric algorithms when I have to transmit files over insecure channel: for example I encrypt backup files stored at my USB stick and I’m sure that if it’s stolen or lost my files are in safety. Encryption without… Read More »Encryption files with GPG without user intervention (batch)