cloud engineer
In Windows a new line, is a CR (carriage return) followed by LF (line feed). In Linux, it’s just LF. If you bring over a text file from Windows to Linux, sometimes you’ll end up with a file with a bunch of ^M at the end of each line, which will breaks a lot of things. To fix, just run dos2unix.
dos2unix file.txt |
dos2unix file.txt
Here’s a command that will compare two files and display the only entries in the first file that are missing in the second file. To do this, there’s a compare command in Linux Bash called comm that comes with several options. The option we are interested in is the comm -23 which exactly does that. Let me demonstrate.
Let’s say file a.txt contains:
one two three four five six seven eight nine ten |
one two three four five six seven eight nine ten
And file b.txt contains:
one three four five nine |
one three four five nine
We then run comm command using the option -23.
comm -23 a.txt b.txt > c.txt |
comm -23 a.txt b.txt > c.txt
The contents of c.txt is:
two six seven eight ten |
two six seven eight ten
Here’s how to keep your SSH timeout alive for a longer period.
Edit /etc/ssh/sshd_config. Adjust interval and count max.
ClientAliveInterval 1200 ClientAliveCountMax 3 |
ClientAliveInterval 1200 ClientAliveCountMax 3
ClientAliveInterval is set to 1200 and ClientAliveCountMax is set to the default which is 3. This means unresponsive SSH clients will be disconnected after approximately 3600 seconds or 1 hour.