-f, --canonicalize canonicalize by following every symlink in every component of the given name recursively; all but the last component must exist
$ readlink -f -- "$(which awk)"/usr/bin/gawk
You can't assign to the positional parameters individually$0 değişkeni - positional parameter
echo $0$0As $0 contains the shell command that is running your shell script or interactive session; when you type $0 in a terminal, you are invoking the command name within the $0 argument variable.
When $0 contains bash; Typing $0 in the terminal, just runs bash. It then runs another bash within the scope of the first one, as a sub-shell.
As it runs another shell, it look like it did nothing, but started another shell session with same environment variables and settings. The shell prompt and current directory are exactly the same, so it look like nothing happened.
If you then try to close the terminal window, while a sub-shell has been invoked, it will tell you there are still background processes running.
What happens when you close the terminal window, is: It signals the first higher level shell Process ID to terminate, but this shell's PID know it has some child PID still attached, and just tells you about it.
qh() {
"$1" --help | grep -- "$2"
}The list of positional parameters can be as long as required and as current resource limits allows. This means that there may be well over 9 elements in the list. As you have already noticed, elements 10 and later may be accessed by adding braces around the number, as in ${12}.
#! /bin/bash
echo $14./file 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
echo ${14}Someone else can probably explain this with much more detail and historical reference but the short answer:/lib
is a place for the essential standard libraries. Think of libraries required for your system to run. If something in /bin or /sbin needs a library that library is likely in /lib.
/usr/lib
the /usr directory in general is as it sounds, a user based directory. Here you will find things used by the users on the system. So if you install an application that needs libraries they might go to /usr/lib. If a binary in /usr/bin or /usr/sbin needs a library it will likely be in /usr/lib.
/var/lib
the /var directory is the writable counterpart to the /usr directory which is often required to be read-only. So /var/lib would have a similar purpose as /usr/lib but with the ability to write to them.
If subscript is @ or *, the word expands to all members of name. These subscripts differ only when the word appears within double quotes. If the word is double-quoted, ${name[*]} expands to a single word with the value of each array member separated by the first character of the IFS special variable, and ${name[@]} expands each element of name to a separate word. When there are no array members, ${name[@]} expands to nothing. If the double-quoted expansion occurs within a word, the expansion of the first parameter is joined with the beginning part of the original word, and the expansion of the last parameter is joined with the last part of the original word.
readarray -t a < pathlist.txt
find "${a[@]}" -type f ....
declare data
data="pig,cow,horse,rattlesnake,"
declare -a my_array
IFS=',' read -r -a my_array <<< "$data"
for item in "${my_array[@]}"; do echo "$item"; donedirs=(A B C D E F G H I J K L M N O P Q R S T U V W X Y Z)
for dir in "${dirs[@]}"
do
mkdir -p $dir
donefor ((i=0 ; i < ${#array[@]} ; i++ )) ; do
echo "${array[i]}"
done#!/bin/bash
array=( "one" "two" "three" "four" "five" )
function get_input() {
read -p "${1}: " number
if [[ " ${array[*]} " == *" ${number} "* ]]
then
echo 'true';
else
get_input 'Try again' # a recursive call of the function
fi
}
get_input 'Enter a number' # the initial call of the functionKind runs a local kubernetes cluster in Docker container and is an effective use to manage local kubernetes cluster deployment. The other alternative for local k8s cluster management is minikube...
kind create cluster --name local-dev