some useful (hopefully) sed command# Unix - 噫吁兮，危乎高哉
t*l
1 楼
*double space a file
sed G
*under UNIX convert DOS newline (CR/LF) to Unix format:
sed 's/.$//'
sed 's/^M$//' #^M should be input like this: Ctrl-V Ctrl-M
*delete leading whitespaces
sed -e 's/^[ ^t]*//' #^t (table): Ctrl-V Ctrl-I
*delete all CONSECUTIVE blank lines from file except the first
sed '/./,/^$/!d' #this will allows 0 blank at top
#in (t)csh, you may want to use \!
sed '/^$/N;/\n$/D' #allowas 1 blank at top, 0 at EOF
*de
sed G
*under UNIX convert DOS newline (CR/LF) to Unix format:
sed 's/.$//'
sed 's/^M$//'
*delete leading whitespaces
sed -e 's/^[ ^t]*//'
*delete all CONSECUTIVE blank lines from file except the first
sed '/./,/^$/!d'
#in (t)csh, you may want to use \!
sed '/^$/N;/\n$/D'
*de