Commands by hkyeakley

Commands by hkyeakley (2)

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Remove blank lines from a file

To save the result, redirect the output to another file. grep -v "^$" file1 > file2
This is sample output - yours may be different.
-1

grep -v "^$" file

hkyeakley · 2009-02-19 18:11:58 3
Quick glance at who's been using your system recently

This command takes the output of the 'last' command, removes empty lines, gets just the first field ($USERNAME), sort the $USERNAMES in reverse order and then gives a summary count of unique matches. Show Sample Output
This is sample output - yours may be different.
```
1 wtmp
      2 reboot
     31 oracle
     15 jsmith
    142 jdoe
      3 root
```
15

last | grep -v "^$" | awk '{ print $1 }' | sort -nr | uniq -c

hkyeakley · 2009-02-18 16:38:59 1

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Find usb device

I often use it to find recently added ou removed device, or using find in /dev, or anything similar. Just run the command, plug the device, and wait to see him and only him

Sort a character string

using perl

Show whats going on restoring files from a spectrum protect backup

spectrum protect's dsmc command shows file names and total amount of restore. This command shows which files are actually open and their siz in GB and highlights the change to the previous output

Short one line while loop that outputs parameterized content from one file to another

The above is an example of grabbing only the first column. You can define the start and end points specifically by chacater position using the following command: $ while read l; do echo ${l:10:40}; done < three-column-list.txt > column-c10-c40.txt Of course, it doesn't have to be a column, or extraction, it can be replacement $ while read l; do echo ${l/foo/bar}; done < list-with-foo.txt > list-with-bar.txt Read more about parameter expansion here: http://wiki.bash-hackers.org/syntax/pe Think of this as an alternative to awk or sed for file operations

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.

Empty Bind9 cache

Occasionally, to force zone updating, cache flush is necessary. The use of this command is better than restart the Bind9 process.

start a VNC server for another user

list files recursively by size

Convert CSV to JSON

Replace 'csv_file.csv' with your filename.

Delete all but the latest 5 files, ignoring directories

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