I am using a shared network and scp to upload files. I do not want to use most of the bandwidth available. How to limit the network rate used by scp in Linux? You can use the -l option of scp to limit the rate of bandwidth. -l limit Limits the used bandwidth, specified in…
How to configure interface bonding to bound to 2 eth interfaces together in Linux, specifically CentOS/RHEL? This tutorial Configuring Interface Bonding on CentOS/RHEL/OEL 6.x introduces setting up interface bonding well on CentOS / RHEL / OEL 6.
I would like to check whether the domain name’s IP has changed in the authoritative DNS server. The system’s configured DNS server may still cache the old IP, which is fine. The question is how to query from the authoritative DNS server the new IP? You can use dig – DNS lookup utility to query…
What suggested web browser in command line? This will be very useful for browsing the Internet from a command line via SSH. You may use Lynx, a fully-featured World Wide Web (WWW) client for users running cursor-addressable, character-cell display devices, in Linux. Homepage: http://lynx.isc.org/ Lynx is a fully-featured World Wide Web (WWW) client for users…
I do not want to have coredump for the developing machine using systemd on Linux? How to disable the coredump function of systemd? You can disable coredump function of systemd by adding this line Storage=none to /etc/systemd/coredump.conf For your reference: Storage= Controls where to store cores. One of “none”, “external”, “journal”, and “both”. When “none”,…
How to un-export an imported variable in Bash on Linux? For example, first, I export a variable MODE like export MODE=debug but I want to unexport the MODE (not turn to be `””`, should be truly non-defined). You can export -n MODE or unset MODE For your reference (from the [`bash` manual](https://www.systutorials.com/docs/linux/man/1-bash/)): export [-fn] [name[=word]]…
When programming in C on Linux, it is common to allocate a buffer for storing the full path of a file. How to get a safe maximum size for allocating buffers for file paths? The header <linux/limits.h> includes macros for the path and file name length limits. On my system (Fedora 21), it is located…
How to get the directory path and file name from a absolute path in Bash on Linux? For example, with “/foo/bar/baz.txt”, it will produce: “/foo/bar/” and “baz.txt”. You also have the basename and dirname commands besides of the basename and dirname C API in Linux: [zma@laptop:~]$ p=”/foo/bar/baz.txt” [zma@laptop:~]$ dirname $p /foo/bar [zma@laptop:~]$ basename $p baz.txt
I got a password protected RSA private key with headers like (I have the password): —–BEGIN RSA PRIVATE KEY—– Proc-Type: 4,ENCRYPTED DEK-Info: AES-256-CBC,… How to decrypt a password protected RSA private key? You can use the openssl command to decrypt the key: openssl rsa -in /path/to/encrypted/key -out /paht/to/decrypted/key For example, if you have a encrypted…
What about the master branch for local git configuration in a git repository to make it track remote master branch? You may append these lines to .git/config in your cloned repository directory: [branch “master”] remote = origin merge = refs/heads/master
This tutorial introduces how to make Chrome accept self assigned ssl keys for websites: https://www.systutorials.com/50204/making-chrome-accept-self-signed-certificates-on-linux/ However, on iPhone, Chrome blocks me from access sites with self assigned keys. How to make Chrome on iPhone also accept the ssl keys? At the time when I wrote this reply, there is no way to add Certificate Authorities…
I experience the program on Linux (Fedora 12) that Chrome reports “Your profile could not be opened correctly.” as follows. How to fix it? Restarting Chrome would not help. Removing the ‘Web Data’ directories from all profiles works for me (Making backup first as the commands will remove your files): cd ~/.config/google-chrome find ./ -name…
Any suggestion on good theme configuration for Fedora 21 Linux? My favorite combination of Window borders, Icons, Controls, Mouse Pointer and Desktop is as follows. All packages and themes are from Fedora repository or the Cinnamon repository. Remember to set the cursor theme for QT application like Google Chrome following: https://www.systutorials.com/4068/configuring-mouse-cursor-style-for-qt-applications-in-gnome-mate-desktop/ For this configuration, the…
A try like the following command failed $ sudo echo “echo hello” > /usr/local/bin/hello with an message bash: /usr/local/bin/hello: Permission denied It seems the writing to the file is executed under the non-root user. How to redirect STDOUT of sudo command on Linux and write the content to the file (/usr/local/bin/hello here) as root? You…
I can only connect to a Linux server by SSH. How to check whether a USB disk is connected to the Linux server? 2 ways I usuaully use: Method One: Check the print out of dmesg After the USB storage is connected and detected by Linux, it may print some messages containing “[sde]” (the new…
On a Linux box, we may allow non-root users mount and umount certain disks, such as /dev/sde1. How to allow non-root users on Linux to mount and unmount disks? Please check the tutorial at Controlling Filesystem Mounting on Linux by Playing with /etc/fstab: Allow non-root users to mount and unmount filesystems.
How to convert all text in a file from upper case to lower case and vice versa on Linux? Convert from upper case to lower case: tr ‘[:upper:]’ ‘[:lower:]’ < input.txt > output.txt Convert from lower case to upper case: tr ‘[:lower:]’ ‘[:upper:]’ < input.txt > output.txt
Any suggestions on good tutorials for screen on Linux? To start with screen: A quick tutorial on screen. After can use the basic functions of screen, you may check out A dummies introduction to GNU Screen and A guide to GNU Screen. During all the progresses, frequently check the screen man page.
Currently, I need to integrate MySQL client into SQLE as SQLE’s client. And then, we just need design/implement a translation layer to transfer MySQL protocol into SQLE engine part (KV+ internal exactly). Mysql-Proxy could solve this problem but it is complex to be only a MySQL server. Therefore, I remoduled MySQL-proxy to be more simple…
Managing a cluster of servers, I would like to notified when a server is started. How to make the Linux servers email me or other admins automatically after they are started? I did this by adding a crontab entry on each servers like @reboot date | mailx -S smtp=smtp://smtp.example.com -s “`hostname` started” -r zma@example.com zma@example.com…