The somewhat scary crevices of the command line. Credit for the documentation of many of the commands in this file goes to the incredible resource provided by Tower.
tail -f - Running this command followed by a file path will output the the last few lines of a file in the command line window, and continue to display additions to the bottom of the file until typing ctrl c. This is extremely handy for monitoring a WordPress debug.log file in the wp-content directory. To output the log, both WP_DEBUG and WP_DEBUG_LOG need to be true in your wp-config.php file.
ctrl-c - MAKE IT STOP! This will generally stop most commands in the middle of execution.
pbcopy < <filename> - Will copy all content from <filename> directly to your clipboard. You can check if the content is there by using the pbpaste command.
pbpaste - Will paste what's on your clipboard to the command line. This is different than standard pasting, which will cause the command line to try to execute commands.
* Doesn't work in non OS X operating systems or may have alternate functionality.
find . -name '*.<ext>' -exec sed -i "" 's/<original>/<replacement>/g' {} \; - Finds the string <original> and replaces it with <replacement> in all <ext> files within the directory.
<command> > <filename> - Direct the output of <command> into <filename> replacing any current contents.
<command> >> <filename> - Append the output of <command> to <filename>.
<command1> | <command2> - Direct the output of <command1> to <command2>. For instance, if you want to copy the result of a command such as pwd to your clipboard using the handy pbcopy command from above you could do pwd | pbcopy, which would put your current directory into your clipboard!
clear - Clear the command line window.
chmod 755 <filename> - Change permissions of <filename> to 755.
chmod -R 600 <directory-name> - Change permissions of <directory-name> (and
its contents) to 600.
chown <user>:<group> <filename> - Change ownership of <filename> to <user> and <group> (add -R to include a directory’s contents).
find <dir-name> -name "<filename>" - Find all files named <filename> inside <dir-name> (use wildcards [*] to search for parts of filenames, e.g. "file.*").
grep "<text>" <filename> - Output all occurrences of <text> inside <filename> (add -i for case-insensitivity).
grep -rl "<text>" <dir-name> - Search for all files containing <text> inside <dir-name>.
ping <host> - Ping <host> and display status.
whois <domain> - Output whois information for <domain>.
curl -O <url/to/file> - Download <file> (via HTTP[S] or FTP).
ssh <username>@<host> - Establish an SSH connection to <host> with user <username>.
scp <file> <user>@<host>:/remote/path - Copy <file> to a remote <host>.