Sed is the ultimate stream editor. SED is the most powerful UNIX command. In its simplest form,
[oracle@usha scripts]$ echo day |sed 's/day/night/' will return
night
[oracle@usha scripts]$ echo day |sed 's/day/night/' will return
night
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# convert DOS newline to Unix format
sed 's/^M$//' # in bash/tcsh, press Ctrl-V then Ctrl-M # Print lines from a file not starting with -- and also remove blank lines cat dbaref.lst|sed -n '/\-/!p'|sed '/^$/d'
"/^$" represents a line that begins and ends without text.
# add text at the begining and end of the line. [oracle@usha scripts]$ cat allsql a.sql test.sql [oracle@usha scripts]$ [oracle@usha scripts]$ cat allsql|sed 's/^/@/' @a.sql @test.sql [oracle@usha scripts]$ cat allsql|sed 's/^/@/'|sed 's/[\t]*$/;/' @a.sql; @test.sql; # delete leading whitespace (spaces, tabs) from front of each line sed 's/^[ \t]*//' [oracle@usha scripts]$ cat a # Original file Sachchida Nand Ojha Andrew Bove [oracle@usha scripts]$ cat a|sed 's/^[ \t]*//' #deleted all leading space Sachchida Nand Ojha Andrew Bove [oracle@usha scripts]$ cat a|sed 's/^[ \t]//' # Deleted one space Sachchida Nand Ojha Andrew Bove [oracle@usha scripts]$ cat a|sed 's/^[\t]*//' # Does Nothing Sachchida Nand Ojha Andrew Bove [oracle@usha scripts]$ # delete trailing white space (spaces, tabs) from end of each line sed 's/[ \t]*$//' [oracle@usha scripts]$ cat a|sed 's/[ \t]*$//' Sachchida Nand Ojha Andrew Bove # delete BOTH leading and trailing white spaces from each line sed 's/^[ \t]*//;s/[ \t]*$//' [oracle@usha scripts]$ cat a|sed 's/^[ \t]*//';sed 's/[ \t]*$//' Sachchida Nand Ojha Andrew Bove #changing PATH from /usr/local/bin to /common/bin [oracle@usha scripts]$ cat a Sachchida Nand Ojha Andrew Bove PATH=/usr/local/bin [oracle@usha scripts]$ cat a|sed 's/\/usr\/local\/bin/\/common\/bin/' Sachchida Nand Ojha Andrew Bove PATH=/common/bin [oracle@usha scripts]$ cat a|sed 's:/usr/local/bin:/common/bin:' Sachchida Nand Ojha Andrew Bove PATH=/common/bin [oracle@usha scripts]$ cat a|sed 's|/usr/local/bin|/common/bin|' Sachchida Nand Ojha Andrew Bove PATH=/common/bin [oracle@usha scripts]$ |
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