Order matters. The way to reason about redirections is to read them from left to right and realize that redirections make streams point at the same place. They don’t make streams point at each other. What does that mean? If you say 2>&1 then you are redirecting stderr to wherever stdout is currently redirected to. … Read more
You need to escape the $ like so: alias a=”awk ‘{print \$1}’ /tmp/textfile” Otherwise your alias is: awk ‘{print }’ /tmp/textfile Which prints the whole file…
Workarounds for not being able to use variables in a sequence brace expression: If the intent is merely to iterate over numbers in a range – as in the OP’s case – the best choice is not to use brace expansion, but instead use bash’s C-style loop – see user000001’s answer. If the specific numbers … Read more
The xterm terminal emulator defines some control sequences to do mouse tracking, you can learn more about them in the section Mouse Tracking in the document ctlseqs for the xterm distribution. If you have xterm installed, you’ll probably have a copy at /usr/share/doc/xterm/ctlseqs.txt.gz or a similar path. Most terminal emulators running on the X Window … Read more
One way would be: while read NAME do echo “$NAME” done < names.txt EDIT: Note that the loop gets executed in a sub-shell, so any modified variables will be local, except if you declare them with declare outside the loop. Dennis Williamson is right. Sorry, must have used piped constructs too often and got confused.
Try something like this: for i in `seq 1 20`; do mkdir -p “folder$i”; find . -type f -maxdepth 1 | head -n 2000 | xargs -i mv “{}” “folder$i”; done Full script version: #!/bin/bash dir_size=2000 dir_name=”folder” n=$((`find . -maxdepth 1 -type f | wc -l`/$dir_size+1)) for i in `seq 1 $n`; do mkdir -p … Read more
eval is a shell builtin, whereas docker exec requires an external utility to be called, so using eval is not an option. Instead, invoke a shell executable in the container (bash) explicitly, and pass it the command to execute as a string, via its -c option: docker exec “app_$i” bash -c “echo ‘server.url=$server_url’ >> /home/app/.app/app.config” … Read more
There are lots of different ways that you could achieve this. I’m going to list one of several possible solutions. I would propose using several different layers of protection to prevent users from running the commands that they shouldn’t be allowed to access. All of the directions here assume that users have their own /home/[username] … Read more
Chris is correct. The source of the loop breaking was SSH using stdin, however guns is correct in is usage of a looping methodology. If you are looping through input (a file with a list of hostnames for example), and calling SSH, you need to pass the -n parameter, otherwise your loop based on input … Read more
Using pv to pipe the file to tar. Firstly, you’ll need to install pv, which on macOS can be done with: brew install pv On Debian or Ubuntu, it can be done with: apt install pv (Thanks @hyperbola!). Pipe the compressed file with pv to the tar command: pv mysql.tar.gz | tar -xz Here’s the … Read more