Issue with activating virtualenv
For me it works when I do these steps: Go to the directory/folder that you want run virtualenv .env then run source .env/bin/activate
bash
How to test if multiple files exist using a Bash script
This solution seems to me more intuitive: if [ `ls -1 /var/log/apache2/access.log.* 2>/dev/null | wc -l ` -gt 0 ]; then echo “ok” else echo “ko” fi
How to expand shell variables in a text file?
This question has been asked in another thread, and this is the best answer IMO: export LOG_FILE_PATH=/expanded/path/of/the/log/file/../logfile.log cat Text_File.msh | envsubst > Text_File_expanded.msh if on Mac, install gettext first: brew install gettext see: Forcing bash to expand variables in a string loaded from a file
How do I check if my local docker image is outdated, without pushing from somewhere else?
You can query the registry API for the image digest and compare it to that of what you’ve pulled. $ cat digest-v2.sh #!/bin/sh ref=”${1:-library/ubuntu:latest}” repo=”${ref%:*}” tag=”${ref##*:}” acceptM=”application/vnd.docker.distribution.manifest.v2+json” acceptML=”application/vnd.docker.distribution.manifest.list.v2+json” token=$(curl -s “https://auth.docker.io/token?service=registry.docker.io&scope=repository:${repo}:pull” \ | jq -r ‘.token’) curl -H “Accept: ${acceptM}” \ -H “Accept: ${acceptML}” \ -H “Authorization: Bearer $token” \ -I -s “https://registry-1.docker.io/v2/${repo}/manifests/${tag}” $ ./digest-v2.sh … Read more
bash printf with new line
printf‘s %b format specifier was meant specifically to replace echo -e (actually, the XSI extension to echo which calls for special interpretation of the arguments by default. -e was never specified and is disallowed by POSIX.), and is identical in virtually every way including a few differences from $’…’ and the format string argument to … Read more
Trace of executed programs called by a Bash script
A simple script I wrote some days ago… # FILE : sctrace.sh # LICENSE : GPL v2.0 (only) # PURPOSE : print the recursive callers’ list for a script # (sort of a process backtrace) # USAGE : [in a script] source sctrace.sh # # TESTED ON : # – Linux, x86 32-bit, Bash 3.2.39(1)-release … Read more
What does $- mean in Bash?
$- prints The current set of options in your current shell. himBH means following options are enabled: H – histexpand: when history expansion is enabled m – monitor: when job control is enabled h – hashall: Locate and remember (hash) commands as they are looked up for execution B – braceexpand: when brace expansion is … Read more
Cannot use mkdir in home directory: permission denied (Linux Lubuntu) [closed]
As @kirbyfan64sos notes in a comment, /home is NOT your home directory (a.k.a. home folder): The fact that /home is an absolute, literal path that has no user-specific component provides a clue. While /home happens to be the parent directory of all user-specific home directories on Linux-based systems, you shouldn’t even rely on that, given … Read more
sed command creating unwanted duplicates of file with -e extension
On OSX sed (BSD) sed requires an extension after -i option. Since it is finding -e afterwards it is adding -e to each input filename. btw you don’t even need -e option here. You can pass an empty extension like this: sed -i ” ‘s/foo/bar/g’ $file Or use .bak for an extension to save original … Read more
Need some explaination of kubectl stdin and pipe
This is a reasonably common, but not universal, Un*x convention. (It is mentioned in the POSIX specification and so most non-Linux Unices will support it as well.) The important detail here is that the kubectl … -f option expects a filename. If you have a file named x.yaml, a more direct way to write what … Read more