Bash Shell Shortcuts

Bash Shell Shortcuts (Alt - escape in MAC)

Ctrl A - Jump to the begin of line(BOL)
Ctrl E - Jump to the end of line(EOL)

Ctrl B - Move back a char
Ctrl F - Move forward a char

Alt B - Move backward word
Alt F - Move forward word

Alt C - Capitalize the word
Alt L - Make word lowercase
Alt U - Make word uppercase

Alt D - Delete word to right
Ctrl D - Delete char from under the cursor
Alt Backspace - Delete backward from cursor

Ctrl U - Delete from cursor to BOL
Ctrl K - Delete from cursor to EOL

Ctrl C - Terminate the command
Ctrl L - Clear the screen
Ctrl R - Search the history backwards
Ctrl xx - Move between BOL and current cursor position
Ctrl Z - Suspend/ Stop the command

Alt < - Move to the first line in the history
Alt > - Move to the last line in the history

Alt ? - Show current completion list
Alt * - Insert all possible completions
Alt / - Attempt to complete filename
Alt . - Yank last argument to previous command
Alt T - swaps the last two words on curser position and before

Tab twice(TT) - all commands
ls TT - files and directories in current directory
stringTT - starting with string commands
/TT - directory with hidden
*TT - sub dirs without hidden
~TT - users from /etc/passwd
$TT - All Sys variables
@TT - Entries from "/etc/hosts"
=TT - Output like ls or dir

who logged in last since last two hours

when we have to check who have logged in last few minutes, here say two hours, or 120minutes.

who | awk -v d=`date +"%Y-%m-%d"` 
                 -v h=`date +"%H"` 
                 -v m=`date +"%M"` 
                ' { split($4,wa,":"); 
                     wc=wa[1]*60+wa[2]; 
                     dc=h*60+m; 
                     if ($3==d && dc-wc<=120 )  printf ("%s\n",$0) 
                  }'

you can change that dc-wc<=120 -- this 120 to any minutes to check

dc - is the current system date time (Hours and minutes converted into minutes), 
wc - is the date time from who command for user logged in 



explained with example

$date
Tue Feb 22 09:01:05 UTC 2011

$ who
sanjeev  pts/0        2011-02-22 07:54 (what.is.the.host)
jro      pts/1        2011-02-21 16:43 (what.is.the.host)
beak     pts/2        2011-02-22 00:49 (beak.has.the.host)
madrose  pts/3        2011-02-22 07:59 (what.is.the.host)
onthepk  pts/4        2011-02-22 08:00 (is.this.the.host)
anita    pts/6        2011-02-22 02:35 (what.is.the.host)

$ who|awk -v d=`date +"%Y-%m-%d"` -v h=`date +"%H"` -v m=`date +"%M"` '{ split($4,wa,":"); wc=wa[1]*60+wa[2]; dc=h*60+m; if ($3==d && dc-wc<=120 )  printf ("%s\n",$0) }'

sanjeev  pts/0        2011-02-22 07:54 (what.is.the.host)
madrose  pts/3        2011-02-22 07:59 (what.is.the.host)
onthepk  pts/4        2011-02-22 08:00 (is.this.the.host)

Occurrences of words in file

Here I am trying to split the words separately on basis of non-aplhanumeric chars or dot, they are replaced by space, and xargs trims more than one spaces or enterkey to one normal space char.
You can include the chars which may be part of your word in the sed ignore block.

cat filename  | sed -e 's/[^a-zA-Z0-9.]/ /g' | xargs | tr ' ' '\n' | sort |  uniq -c | sort -nr -k1,2

voila you should get the most occured word on top.
This is output for the above text.




   4 the
   2 xargs
   2 word
   2 to
   2 space
   2 sort
   2 sed
   2 or
   2 one
   2 on
   2 of
   2 chars
   1 zA
   1 your
   1 you
   1 words
   1 which
   1 voila
   1 uniq
   1 trying
   1 trims
   1 tr
   1 top.
   1 they
   1 than
   1 split
   1 spaces
   1 should
   1 separately
   1 s
   1 replaced
   1 part
   1 occured
   1 nr
   1 normal
   1 non
   1 n
   1 most
   1 more
   1 may
   1 include
   1 in
   1 ignore
   1 get
   1 g
   1 filename
   1 enterkey
   1 e
   1 dot
   1 char.
   1 cat
   1 can
   1 c
   1 by
   1 block.
   1 be
   1 basis
   1 are
   1 aplhanumeric
   1 and
   1 am
   1 a
   1 Z0
   1 You
   1 I
   1 Here
   1 9.