shell学习札记

#!/bin/bash
# script to send simple email
# email subject
SUBJECT="SET-EMAIL-SUBJECT"
# Email To ?
EMAIL="admin@somewhere.com"
# Email text/message
EMAILMESSAGE="/tmp/emailmessage.txt"
echo "This is an email message test"> $EMAILMESSAGE
echo "This is email text" >>$EMAILMESSAGE
# send an email using /bin/mail
/bin/mail -s "$SUBJECT" "$EMAIL" < $EMAILMESSAGE

awk '$2 == "waptest.taobao.com" { print $0 }' /etc/host

awk '$2 ~ "waptest*" { print $0 }' /etc/hosts

wuzhong@TAOBAOWDS46:~/bin$ more ed.script 
g/^k/s/k.*/kkkkkkkkk/g
w
q
wuzhong@TAOBAOWDS46:~/bin$ ed -s txt < ed.script 

#!/bin/bash

set -x
TO_STRING=123
FROM_STRING=^k
FROM_STRING2=k.*

echo $TO_STRING  $FROM_STRING $FROM_STRING2

#cat ed.script | while read a_line
#do
# eval echo $a_line   变量替换
#done | more

echo "g/$FROM_STRING/s/$FROM_STRING2/$TO_STRING/g" > tmp
echo "w" >> tmp
echo "q" >> tmp

ed -s txt < tmp

ed -s txt << EOF
g/$FROM_STRING/s/$FROM_STRING2/$TO_STRING/g
w
q
EOF

CAT 格式化输出
wuzhong@TAOBAOWDS46:~/bin$ more example_cat.sh 
#!/bin/bash


AAA=AAAaaaaaa
cat > tmp << TAG
  111111111
  2222222222
  333333333
  $wtm_daily_host
  $AAA
TAG