Display only files and folders that are symbolic links in tcsh or bash
Find all the symbolic links in a directory: ls -l `find /usr/bin -maxdepth 1 -type l -print` For the listing of hidden files: ls -ald .*
linux
Removing Windows newlines on Linux (sed vs. awk)
You can use the command line tool dos2unix dos2unix input Or use the tr command: tr -d ‘\r’ <input >output Actually, you can do the file-format switching in vim: Method A: :e ++ff=dos :w ++ff=unix :e! Method B: :e ++ff=dos :set ff=unix :w EDIT If you want to delete the \r\n sequences in the file, … Read more
Get the characters after the last index of a substring from a string
If the string is in a variable: $ foo=”header. stuff. more stuff” $ echo “${foo##*. }” more stuff If there are multiple instances of “. ” (as in my example) and you want everything after the first occurrence, instead of the last, just use one #: $ echo “${foo#*. }” stuff. more stuff
How do I replace single quotes with another character in sed?
Try to keep sed commands simple as much as possible. Otherwise you’ll get confused of what you’d written reading it later. #!/bin/bash sed “s/’/ /g” myfile.txt
Finding executable files using ls and grep
Do you need to use ls? You can use find to do the same: find . -maxdepth 1 -perm -111 -type f will return all executable files in the current directory. Remove the -maxdepth flag to traverse all child directories. You could try this terribleness but it might match files that contain strings that look … Read more
Using output of awk to run command
Use system from within awk: awk ‘{ system(“openssl s_client -connect host:port -cipher ” $1) }’ ciphers.txt
Does libcxxabi makes sense under linux? What are the benefits?
You should not use libcxxabi directly. To my understanding it is a kind of platform abstraction library, providing low level functions needed to implement libcxx. If you are asking about using libcxx or libstdc++, the differences are mostly the license, newer standard version completeness (the clang project seems slightly faster in implementing recent C++ revisions) … Read more
xvfb-run on OS X
X11 is no longer included with OS X: https://support.apple.com/en-us/HT201341 X11 server and client libraries for OS X are available from the XQuartz project: http://xquartz.macosforge.org/ I’m not sure if it includes all the other X goodies like Xvfb. In that case you could compile it yourself; with these options: –disable-xquartz –enable-xvfb –enable-xnest –enable-kdrive More info here: … Read more
How to Dynamically Allocate Memory Using Assembly and System Calls Under Linux
On Linux mmap2 is a sensible system call to use for this at a low level. It takes 6 arguments, so in IA32 you can call it using: mov eax, 192 ; mmap2 xor ebx, ebx ; addr = NULL mov ecx, 4096 ; len = 4096 mov edx, $7 ; prot = PROT_READ|PROT_WRITE|PROT_EXEC mov … Read more
How / Where to find Linux Kernel Bugs to Fix?
1. Yes, you are right, one of the places to look is the kernel bug tracker. Searching the Linux kernel mailing list as well as the subsystem-related mailing lists could also be helpful but is probably more difficult. 2. The main kernel mailing list is here. You can find subscription instructions there. 3. There is … Read more