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> $null)) { # do something } But since docker images only takes REPOSITORY as parameter, … Read more
Single [] are posix shell compliant condition tests. Double [[]] are an extension to the standard [] and are supported by bash and other shells (e.g. zsh, ksh). They support extra operations (as well as the standard posix operations). For example: || instead of -o and regex matching with =~. A fuller list of differences … Read more
It is better to handle this with “with” to close the descriptor automatically for you. This will work with both 2.7 and python 3. with open(‘/path/to/my/file.txt’, ‘r’) as f: print(f.read())
You can run your command without any additional syntax. For example, the following checks the exit code of grep to determine whether the regular expression matches or not: if ! grep -q “$word” /usr/share/dict/words then echo “Word $word is not valid word!” fi
Alternative ways to write these options. You can write mysql -u “$MYSQL_ROOT” -p”$MYSQL_PASS” -e “SHOW DATABASES” If [password is] given, there must be no space between –password= or -p and the password following it. If no password option is specified, the default is to send no password. to pass empty strings as separate arguments. Your … Read more
[ … ] doesn’t do pattern matching. /* is being expanded to the contents of /, so effectively you have if [ “$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
Use an array awk ‘{count[$3]++} END {for (word in count) print word, count[word]}’ file If you want “block” specifically: END {print count[“BLOCK”]}
First, get file name without the path: filename=$(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
I do understand I’m adding an answer to an old question, but I feel the tooling has improved lately and would like to give additional suggestions in order to help out others who are viewing this question. I have recently found TomDoc.sh, which uses TomDoc style comments in shell scripts. The tool provided can then … Read more