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infile search and replace on N files (including backup of the files)
the addition of ".bk" to the regular "pie" idiom makes perl create a backup of every file with the extension ".bk", in case it b0rks something and you want it back

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Alert visually until any key is pressed
I learned a few things reading this command. But I did run into a few issues: 1. On systems that don't use GNU echo (e.g. macOS 10.14.5 Mojave), the e option may not be supported. In this case ANSI escape codes will echoed as text and the terminal will not flash, like this: \e[?5h\e[38;5;1m A L E R T Thu Jun 20 16:31:29 PDT 2019 2. Since the read command strips\ignores leading backslashes, if a user types the backslash character once in the loop, it will not break. Typing backslash twice in a loop will break as expected. 3. The foreground color is set to red (\e[38;5;1m) on every loop. This could be set once before we call while, and then reset once when the loop breaks. 4. Instead of resetting the foreground color when it breaks, the video mode is set back to normal (\e[?5l). This has the effect of leaving the terminal text red until it is manually reset. The alternative I'm proposing here addresses these issues. I tested it on macOS and Arch Linux.

ssh autocomplete based on ~/.ssh/config
I sue this in my .bashrc file This will also do auto-completion for scp and sftp

diff two svn repos ignoring spaces,tabs and svnfiles

Create a mirror of a local folder, on a remote server
Create a exact mirror of the local folder "/root/files", on remote server 'remote_server' using SSH command (listening on port 22) (all files & folders on destination server/folder will be deleted)

See why a program can't seem to access a file
Sometimes a program refuses to read a file and you're not sure why. You may have display_errors turned off for PHP or something. In this example, fopen('/var/www/test/foo.txt') was called but doesn't have read access to foo.txt. Strace can tell you what went wrong. E.g., if php doesn't have read access to the file, strace will say "EACCESS (Permission denied)". Or, if the file path you gave doesn't exist, strace will say "ENOENT (No such file or directory)", etc. This works for any program you can run from the command-line, e.g., strace python myapp.py -e open,access... Note: the above command uses php-cli, not mod_php, which is a different SAPI with diff configs, etc.

Picture Renamer

generate file list modified since last commit and export to tar file
################################################################################ # get all modified files since last commit and zip them to upload to live server ################################################################################ # delete previous tar output file rm mytarfile.tar -rf #rm c:/tarOutput/*.* -rf # get last commit id and store in variable declare RESULT=$(git log --format="%H" | head -n1) # generate file list and export to tar file git diff-tree -r --no-commit-id --name-only --diff-filter=ACMRT $RESULT | xargs tar -rf mytarfile.tar # extract tar files to specified location tar -xf mytarfile.tar -C c:/tarOutput

Adequately order the page numbers to print a booklet
Useful if you don't have at hand the ability to automatically create a booklet, but still want to. F is the number of pages to print. It *must* be a multiple of 4; append extra blank pages if needed. In evince, these are the steps to print it, adapted from https://help.gnome.org/users/evince/stable/duplex-npage.html.en : 1) Click File ▸ Print. 2) Choose the General tab. Under Range, choose Pages. Type the numbers of the pages in this order (this is what this one-liner does for you): n, 1, 2, n-1, n-2, 3, 4, n-3, n-4, 5, 6, n-5, n-6, 7, 8, n-7, n-8, 9, 10, n-9, n-10, 11, 12, n-11... ...until you have typed n-number of pages. 3) Choose the Page Setup tab. - Assuming a duplex printer: Under Layout, in the Two-side menu, select Short Edge (Flip). - If you can only print on one side, you have to print twice, one for the odd pages and one for the even pages. In the Pages per side option, select 2. In the Page ordering menu, select Left to right. 4) Click Print.


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