After 3 years and 2 months… I received a lot of points because of this question here on stackoverflow. So yesterday I decided to revisit this topic :). Using fcntl and F_LOG2PHYS is possible to check if files are using same physical blocks or not. So I made an utility using this idea and put … Read more
The sha-bang ( #!) [1] at the head of a script tells your system that this file is a set of commands to be fed to the command interpreter indicated. The #! is actually a two-byte [2] magic number, a special marker that designates a file type, or in this case an executable shell script … Read more
If all lines in the input file are of this format, then simply sourcing it will set the variables: source nameOfFileWithKeyValuePairs or . nameOfFileWithKeyValuePairs
Accrding to: http://www.vias.org/linux-knowhow/bbg_sect_08_02_01.html : -r If this option is given, backslash does not act as an escape character. The backslash is considered to be part of the line. In particular, a backslash-newline pair may not be used as a line continuation. It works on my machine. $ echo ‘\&|’ | while read -r in; do … Read more
Using wait() or waitpid() It is not possible on Unix and derivatives using POSIX functions like wait() and waitpid(). The exit status information returned consists of two 8-bit fields, one containing the exit status, and the other containing information about the cause of death (0 implying orderly exit under program control, other values indicating that … Read more
Probably the simplest thing is: $ ssh -t host ‘cmd1; cmd2; sh -i’ If you want to set variables, do: $ ssh -t host ‘cmd1; cmd2; FOO=hello sh -i’ Note that this is a terrible hack, and you would be much better off putting your desired initial commands in a script and doing: $ scp … Read more
npx has a –yes flag you can use to bypass the prompt: npx –yes some-npm-package This is undocumented if you run npx –help, but the documentation for this flag is hidden in the command’s “description” on the NPM website. There is also a –no flag available if you need to reject the prompt instead.
Instead of storing the output of grep in a variable and then checking whether the variable is empty, you can do this: if grep -q “poet” $file_name then echo “poet was found in $file_name” fi ============ Here are some commonly used tests: -d FILE FILE exists and is a directory -e FILE FILE exists -f … Read more
Another way: convert *.jpg -resize 80% -set filename:f ‘%t’ ../’%[filename:f].jpg’ Will place converted files in the folder above. The option -set filename:f ‘%t’ sets the property filename:f to the current filename without the extension. Properties beginning with filename: are a special case that can be referenced in the output filename. Here we set it to … Read more
With BSD xargs (for OS X and FreeBSD), you can use -J which was built for this: find . -name some_pattern -print0 | xargs -0 -J % mv % target_location That would move anything matching some_pattern in . to target_location With GNU xargs (for Linux and Cygwin), use -I instead: find . -name some_pattern -print0 … Read more