The problem is like this: I would like to send a GET request using curl and the content has spaces, such as curl “http://example.com/send?msg=hello world” The space and the “world” will be left away if this command is executed directory on Linux. How to encode spaces in curl request URL? You can use the –date-urlencode…
One of HDFS cluster’s hdfs dfsadmin -report reports: Under replicated blocks: 139016 Blocks with corrupt replicas: 9 Missing blocks: 0 The “Under replicated blocks” can be re-replicated automatically after some time. How to handle the missing blocks and blocks with corrupt replicas in HDFS? Understanding these blocks A block is “with corrupt replicas” in HDFS…
I have a Linux box and it is connected to a network through a network adapter, say gate. How to find what is the current speed (10Mbps, 100Mbps or 1000Mbps) of the adapter? You can find the network adapter speed by the ethtool command: ethtool: query or control network driver and hardware settings For example,…
After I installed XEN hypervisor, the tty0 (CTRL+ALT+F1) prints “powernow-k8 transition frequency failed” to STDOUT continously, how to solve it? sudo rmmod powernow_k8 From https://lists.debian.org/debian-user/2013/01/msg00754.html How to make the settings persistent (take effect after reboot)? 1, Create script file ‘/etc/init.d/stop_pwoerk8.sh’ as follows. harry2vera@node1:/etc/init.d$ cat stop_pwoerk8.sh #! /bin/sh rmmod powernow_k8 2, Add the full PATH of…
When you replace dynamic IP to static IP, you may need to restart your netwrok on Debian as follows. $sudo /etc/init.d/networking restart … …. reconfiguring network interfaces…rtnetlink answers file exists … However, error happens here “rtnetlink answers file exists”. How to solve it??? Run following commands could solve this problem # ip addr flush dev…
How to exclude last N columns of a string in bash? The point is that the number of columns in each line is uncertain (but > N). For example, I would like to remove the last 2 columns separated by ‘.’ in the following lines. systemd.3.gz systemd.mount.3.gz systemd.mount.f.3.gz The simple cut command cut -d’.’ -f1…
How to sort all the files in a directory and subdirectories recursively by modification time on Linux? You can make use of find (GNU find, or plus stat), sort and sed together to achieve recursively sort files by modification time: find . -type f -printf ‘%T@ %pn’ | sort -k 1 -n | sed ‘s/^[^…
YouCompleteMe for Vim on Fedora 21 reports this error: [zma@laptop:~/.vim/bundle/YouCompleteMe]$ ./install.sh — The C compiler identification is GNU 4.9.2 — The CXX compiler identification is GNU 4.9.2 — Check for working C compiler: /usr/bin/cc — Check for working C compiler: /usr/bin/cc — works — Detecting C compiler ABI info — Detecting C compiler ABI info…
Where can I find a list of all Xen hypervisor command line options that can be passed to Xen hypervisor during boot? This page lists all options of Xen hypervisor: Xen Hypervisor Command Line Options
I have made some eps figures for my paper but now I wanna modify them. How to edit them now? You may try inkscape on Linux: https://inkscape.org/en/ It can edit eps files.
Unfortunately, my C: drive is almost full. Most of the space are used by the user home under C:Users. How can I move the home directory to another drive while not affecting the user’s usage of Windows. On Linux/Unix, moving the directory to another drive/partition and then keeping a softlink is enough. But how to…
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 quite VirtualBox scale mode? Use this hot key shortcut to quit VirtualBox scale mode Right_Ctrl + c
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…
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]]…
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 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…
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…