using awk to append numbers to the start of a list

awk '{print NR " " $0}' list > list-numbered

using awk to print a range of lines from a list

awk '$1 == 2 , $1 == 7' list

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display non blank and non commented lines in file

filter blank and comment lines from file

cat /etc/ssh/sshd_config  | grep -v \# | sed '/^$/d' 
cat /etc/ssh/sshd_config  | grep -v \# | awk 'NF'
grep  -v ^# /etc/samba/smb.conf | grep -v ^\; | awk 'NF'

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Use awk to auto generate repeating block of code eg.. creating a really long if else or case statement

I was creating a keyboard mapper program and instead of typing loads of else if statements manually... I create a paired list of the input/match and the output/action and used the awk script below to generate the else if statements.

A 14
B 2F
C 26
D 24
E 22
F 2C
G 2D
H 35
I 3A
J 34
K 3C
L 44
M 36
N 37
O 42
P 4A
Q 12
R 2A
S 1C
T 2B
U 32
V 2E
W 1A
X 1E
Y 33
Z 16

use awk to generate

#the spaces in the following line are required
cat inputed_list | awk '{ print "       else if ( c = '"'"'"$1"'"'"' ){\n             key_value = "$2";\n            single_upper(c);\n             }"}'

the output c code

  else if ( c = 'T' ){
         key_value = 2B;
         single_upper(c);
         }
  else if ( c = 'U' ){
         key_value = 32;
         single_upper(c);
         }
  else if ( c = 'V' ){
         key_value = 2E;
         single_upper(c);
         }
  else if ( c = 'W' ){
         key_value = 1A;
         single_upper(c);
         }
  else if ( c = 'X' ){
         key_value = 1E;
         single_upper(c);
         }
  else if ( c = 'Y' ){
         key_value = 33;
         single_upper(c);
         }
  else if ( c = 'Z' ){
         key_value = 16;
         single_upper(c);

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Simple script using awk to dump a list of the filesystems that are over 70% full to a file in /tmp

#!/bin/bash
#seamus Dec 2004
out=/tmp/diskusage
name=`uname -n`
date=`date`
echo >  $out

echo $name $date >> $out 
df -k | awk '{if( $5 > 70 ) print $0 }'  | awk '!/Filesystem/' >> $out
cat $out

use sed to append spaces to start of each line for markdown input

cat {file} | sed s/^/\ \ \ \ /g

script to replace the spaces in filenames with underscrores

#!/bin/bash
# this script was created to replace the spaces in filenames with underscrores
#seamus Dec 2004
#if [ $1 != do ] || [ $1 != check ]
#then 
#   echo USAGE: do or check 
#   exit
#
#fi
case "$1" in
do)
    for i in *
    do 
    mv "$i" `echo -n "$i" | sed 's/\ /_/g'`
    done
;;
check) 
        for i in *
        do
        echo;echo -n "rename" 
            echo;echo  "$i" 
        echo  to.......
        echo -n "$i" | sed 's/\ /_/g'
    echo
    done
;;
*)
    echo USAGE: do or check
esac