Homebrew is nice. However unlike brew and npm, gem does not make aliases in /usr/local/bin automatically. Solution I went for a very simple approach (as of March 2020): # Based on “`brew –prefix ruby`/bin” export PATH=/usr/local/opt/ruby/bin:$PATH # Based on “`gem environment gemdir`/bin” export PATH=/usr/local/lib/ruby/gems/3.0.0/bin:$PATH Add this to your .bashrc (or .bash_profile, .zshrc, etc.). That’s it! … Read more
if id -nG “$USER” | grep -qw “$GROUP”; then echo $USER belongs to $GROUP else echo $USER does not belong to $GROUP fi Explanation: id -nG $USER shows the group names a user belongs to. grep -qw $GROUP checks silently if $GROUP as a whole word is present in the input.
Short answer: HISTSIZE is the number of lines or commands that are stored in memory in a history list while your bash session is ongoing. HISTFILESIZE is the number of lines or commands that (a) are allowed in the history file at startup time of a session, and (b) are stored in the history file … Read more
You can simplify things a bit by putting command right in the test and doing increments a bit differently. Otherwise the script looks fine: NEXT_WAIT_TIME=0 until (( NEXT_WAIT_TIME == 5 )) || cmd; do sleep “$(( NEXT_WAIT_TIME++ ))” done (( NEXT_WAIT_TIME < 5 ))
Change the line where you define selectedexpression to selectedexpression=${expressions[ $RANDOM % ${#expressions[@]} ]} You want your index into expression to be a random number from 0 to the length of the expression array. This will do that.
You have to reset all arguments. To change, e.g., argument $3: set — “${@:1:2}” “new_arg3” “${@:4}” Basically you set all arguments to their current values, except for the one(s) that you want to change. set — is also specified by POSIX 7. The “${@:1:2}” notation is expanded to the two (hence the 2 in the … Read more
Certainly, how it’s done depends on your shell. In Bash, you can use single quotes around the message and can just leave the quote open, which will make Bash prompt for another line, until you close the quote. Like this: git commit -m ‘Message goes here’ Alternatively, you can use a “here document” (also known … Read more
If you docker run without attaching a tty, and only call bash, then bash finds nothing to do, and it exits. That’s because by default, a container is non-interactive, and a shell that runs in non-interactive mode expects a script to run. Absent that, it will exit. To run a disposable new container, you can … Read more
What you’ve written actually almost works (it would work if all the variables were numbers), but it’s not an idiomatic way at all. (…) parentheses indicate a subshell. What’s inside them isn’t an expression like in many other languages. It’s a list of commands (just like outside parentheses). These commands are executed in a separate … Read more
You are probably looking for the timeout command in coreutils. Since it’s a part of coreutils, it is technically a C solution, but it’s still coreutils. info timeout for more details. Here’s an example: timeout 5 /path/to/slow/command with options