When you double-quote a path, you’re stopping the tilde expansion. So there are a few ways to do this: cd ~/”My Code” cd ~/’My Code’ The tilde is not quoted here, so tilde expansion will still be run. cd “$HOME/My Code” You can expand environment variables inside double-quoted strings; this is basically what the tilde … Read more
I usually test the result of docker images -q (as in this script): if [ -z “$(docker images -q myimage:mytag 2> /dev/null)” ]; then # do something fi On Powershell (comment from Garret Wilson): if (!(docker images -q myimage:mytag 2> $null)) { # do something } But since docker images only takes REPOSITORY as parameter, … Read more
Single [] are posix shell compliant condition tests. Double [[]] are an extension to the standard [] and are supported by bash and other shells (e.g. zsh, ksh). They support extra operations (as well as the standard posix operations). For example: || instead of -o and regex matching with =~. A fuller list of differences … Read more
You can run your command without any additional syntax. For example, the following checks the exit code of grep to determine whether the regular expression matches or not: if ! grep -q “$word” /usr/share/dict/words then echo “Word $word is not valid word!” fi
[ … ] doesn’t do pattern matching. /* is being expanded to the contents of /, so effectively you have if [ “$DIR” = /bin /boot /dev /etc /home /lib /media … /usr /var ] or something similar. Use [[ … ]] instead. if [[ “$DIR” = /* ]]; then For POSIX compliance, or if … Read more
First, get file name without the path: filename=$(basename — “$fullfile”) extension=”${filename##*.}” filename=”${filename%.*}” Alternatively, you can focus on the last “https://stackoverflow.com/” of the path instead of the ‘.’ which should work even if you have unpredictable file extensions: filename=”${fullfile##*/}” You may want to check the documentation : On the web at section “3.5.3 Shell Parameter Expansion” … Read more
/usr/bin/env exports values passed in key=value pairs into the environment of any program it’s used to invoke. kubectl -n nmspc exec “$POD” — env curIP=123 script01 Note that you should never use $runScript or any other unquoted expansion to invoke a shell command. See BashFAQ #50 — I’m trying to put a command in a … Read more
NAME paste — merge corresponding or subsequent lines of files SYNOPSIS paste [-s] [-d list] file … DESCRIPTION The paste utility concatenates the corresponding lines of the given input files, replacing all but the last file’s newline characters with a single tab character, and writes the resulting lines to standard output.
Bash does not support local functions, but depending on your specific script and architecture you can control the scope of your function name through subshells. By replacing the {..} with (..) in your definition, you’ll get the output you want. The new definition of usage will be limited to the function, but so will e.g. … Read more
declare inside a function doesn’t work as expected. I needed read-only global variables declared in a function. I tried this inside a function but it didn’t work: declare -r MY_VAR=1 But this didn’t work. Using the readonly command did: func() { readonly MY_VAR=1 } func echo $MY_VAR MY_VAR=2 This will print 1 and give the … Read more