Commands tagged fields (2)

  • Once you get into advanced/optimized scripts, functions, or cli usage, you will use the sort command alot. The options are difficult to master/memorize however, and when you use sort commands as much as I do (some examples below), it's useful to have the help available with a simple alias. I love this alias as I never seem to remember all the options for sort, and I use sort like crazy (much better than uniq for example). # Sorts by file permissions find . -maxdepth 1 -printf '%.5m %10M %p\n' | sort -k1 -r -g -bS 20% 00761 drwxrw---x ./tmp 00755 drwxr-xr-x . 00701 drwx-----x ./askapache-m 00644 -rw-r--r-- ./.htaccess # Shows uniq history fast history 1000 | sed 's/^[0-9 ]*//' | sort -fubdS 50% exec bash -lxv export TERM=putty-256color Taken from my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html Show Sample Output


    3
    alias sorth='sort --help|sed -n "/^ *-[^-]/s/^ *\(-[^ ]* -[^ ]*\) *\(.*\)/\1:\2/p"|column -ts":"'
    AskApache · 2010-06-10 21:30:31 10
  • You can display, save and restore the value of $IFS using conventional Bash commands, but these functions, which you can add to your ~/.bashrc file make it really easy. To display $IFS use the function ifs shown above. In the sample output, you can see that it displays the characters and their hexadecimal equivalent. This function saves it in a variable called $saveIFS: sifs () { saveIFS=$IFS; } Use this function to restore it rifs () { IFS=$saveIFS; } Add this line in your ~/.bashrc file to save a readonly copy of $IFS: declare -r roIFS=$IFS Use this function to restore that one to $IFS rrifs () { IFS=$roIFS; } Show Sample Output


    2
    ifs () { echo -n "${IFS}"|hexdump -e '"" 10/1 "'\''%_c'\''\t" "\n"' -e '"" 10/1 "0x%02x\t" "\n\n"'|sed "s/''\|\t0x[^0-9]//g; $,/^$/d"
    dennisw · 2009-10-10 22:41:35 8

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Merge files, joining each line in one line

Change every instance of OLD to NEW in file FILE
Very quick way to change a word in a file. I use it all the time to change variable names in my PHP scripts (sed -i 's/$oldvar/$newvar/g' index.php)

Check syntax of all Perl modules or scripts underneath the current directory
Finds all *.p[ml]-files and runs a perl -c on them, checking whether Perl thinks they are syntactically correct

Find usb device in realtime
Using this command you can track a moment when usb device was attached.

Remind yourself to leave in 15 minutes
If you spend most of your time in front of the terminal, leave is a useful reminder. Leave can have absolute form: leave 1555 reminds you to leave at 3:55PM

Calculate days on which Friday the 13th occurs (inspired from the work of the user justsomeguy)
Friday is the 5th day of the week, monday is the 1st. Output may be affected by locale.

Creates a symbolic link or overwrites an existing one
-n: dereference the existing link -v: (optional) to be sure of what is being done -f: force the deletion of the existing one -s: creates a symlink Be careful: the destination can also be a file or a directory and it will be overwritten.

Write comments to your history.
A null operation with the name 'comment', allowing comments to be written to HISTFILE. Prepending '#' to a command will *not* write the command to the history file, although it will be available for the current session, thus '#' is not useful for keeping track of comments past the current session.

Create multiple subfolders in one command.
Instead of typing separate commands to create various subfolders, we can create multiple subfolders by listing them between brackets and separated by commas.

Monitor changed files into a log file, with day rotation, using fswatch (MacOS)
This command monitors changes in the current folder structure (subfolders included) and files, and log it into a hidden file in the same folder, called `.file_changes_YYMMDD.log`. Modify the `--exclude` parameters to define what should be skipped.


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