Using sed in UNIX - global changes to strings Oracle Tips by Burleson Consulting

Using sed in UNIX

The sed command is used to make global changes to strings in UNIX files. For example, below we have a utility that will change all strings in a directory from one string to another. This is sort of a “change all” utility within UNIX. The format of the sed command is:

sed/oldstring/newstring > new file location

The sed utility always makes a new copy of every file it changes, so special care is required to make an in-place change. Note the sed line in this script where sed changes the old string to the new string in all files in the directory. Note that this script makes a backup of the files in a tmp sub-directory before issuing the change.

chg_all.sh
#!/bin/ksh

tmpdir=tmp.$$

mkdir $tmpdir.new

for f in $*
do
sed -e 's/oldstring/newstring/g' < $f > $tmpdir.new/$f
done

# Make a backup first!
mkdir $tmpdir.old
mv $* $tmpdir.old/

cd $tmpdir.new
mv $* ../

cd ..
rmdir $tmpdir.new

The above is an excerpt from the "Oracle9i UNIX Administration Handbook" by Oracle press, authored by Donald K. Burleson.