Girkers wrote:
I have used
Code:
sed
in one of my scripts but the problem is, it doesn't work properly. I can give it an input file, but I have no way of outputing back to the same file.Classic rookie mistake.
(Sorry, I've taught this stuff, after a while to have to laugh or you cry.) Write to a temp file and replace the old file with that. When I'm writing production quality shell script I usually have a little shell function that "edits a file in place" leaving a backup file with the original contents. Hang on and lt me hunt up an example... Hmmm.. Nothing suitable shows up since I tend to do that with a hunk of Python I wrote these days... Well, here goes nothing... Be warned this will be VERY idomatic and I'll assume BASH so don't say #!/bin/sh at the beginning and expect good things... And this is off the top of my head and COMPLETELY UNTESTED!Code:
# I've always got these around... but they're usually much more elaborate...
warn () {
echo "Warning: $*"
}
fatal () {
echo "Fatal! $*"
exit 2
}
d='/' # In case / is just too painful
replaceStringInFile () {
# I use this order to make this easier to extend
from="$1"
to="$2"
file="$3"
[ $# -eq 3 ] || { warn "bad arg count" ; return 1; }
[ -z "$from" ] || { warn "No from pattern" ; return 1; }
# Note that an empty to pattern makes perfect sense...
[ -z "$file" ] || { warn "No filename given" ; return 1; }
[ -f "$file" ] || { warn "No such file: $file" ; return 1; }
[ -r "$file" ] || { warn "Cannot read file: $file" ; return 1; }
[ -w "$file" ] || { warn "Cannot write file: $file" ; return 1; }
# You should also check that the directory is writable, etc., ...
tmpFile="$file.tmp.$$"
cp -p "$file" "$tmpFile" || {
warn "Cannot create temporary file: $tmpFile" ; return 1; }
sed -e "$d$from$ds$d$d$to$dg" <"$file" >"$tmpFile" || {
warn "Cannot edit file: $file" ; return 1; }
mv "$file" "$file~" || {
warn "Cannot rename file: $file" ; return 1; }
mv "$tmpFile" "$file" || {
warn "Cannot replace file: $file" ; return 1; }
return 0
}
warn () {
echo "Warning: $*"
}
fatal () {
echo "Fatal! $*"
exit 2
}
d='/' # In case / is just too painful
replaceStringInFile () {
# I use this order to make this easier to extend
from="$1"
to="$2"
file="$3"
[ $# -eq 3 ] || { warn "bad arg count" ; return 1; }
[ -z "$from" ] || { warn "No from pattern" ; return 1; }
# Note that an empty to pattern makes perfect sense...
[ -z "$file" ] || { warn "No filename given" ; return 1; }
[ -f "$file" ] || { warn "No such file: $file" ; return 1; }
[ -r "$file" ] || { warn "Cannot read file: $file" ; return 1; }
[ -w "$file" ] || { warn "Cannot write file: $file" ; return 1; }
# You should also check that the directory is writable, etc., ...
tmpFile="$file.tmp.$$"
cp -p "$file" "$tmpFile" || {
warn "Cannot create temporary file: $tmpFile" ; return 1; }
sed -e "$d$from$ds$d$d$to$dg" <"$file" >"$tmpFile" || {
warn "Cannot edit file: $file" ; return 1; }
mv "$file" "$file~" || {
warn "Cannot rename file: $file" ; return 1; }
mv "$tmpFile" "$file" || {
warn "Cannot replace file: $file" ; return 1; }
return 0
}
You should be able to generalize that to other sed commands easily enough... Or even replace the from and to arguments with a sed command to be executed.
Girkers wrote:
Also I am trying to set up my script so you can say use or no at the start so it will only run the parts that you want it too, eg:
...
I know how to set the variables, but how about the if statement?
Code:
kernel=yes
webmin=yes
samba=no
webmin=yes
samba=no
...
Code:
if kernel=yes then ...
I know how to set the variables, but how about the if statement?
Something like this. Note the spaces and the quotes are VITAL.
Code:
if [ "$variableNameHere" = "yes" ] ; then
doYesStuff
else
doNoStuff
fi
doYesStuff
else
doNoStuff
fi
Or this:
Code:
case "$var" in
[Yy]|[Yy][Ee][Ss])
doYesStuff
;;
[Nn]|[Nn][Oo])
doNoStuff
;;
*)
doWTHStuff
;;
esac
[Yy]|[Yy][Ee][Ss])
doYesStuff
;;
[Nn]|[Nn][Oo])
doNoStuff
;;
*)
doWTHStuff
;;
esac