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I've got a difficult one for ya I've been trying to work this one out for yonks but not yet been able to do it...
What I want to be able to do is create something like this...
1. Get a file (i.e. html or anything)
2. Grep a line (or more) out of it and replace it with something else
3. Save it in the exact format it was in (apart from changes)
#!/bin/sh
#
# Replace lines in a file that match the given regex
#
# (c) 2003 Kyle Gibson, free for non-commercial use
# may be redistributed provided this header is left
# in tact. Feel free to modify.
#
# License: GPL
##################################
usage()
{
echo "Usage: $0 [file] [nfile] [replace] [new]"
exit 1;
}
# file must be readable
test -r "$1" || usage
# the file we put this into should be specified
test -z "$2" && usage
# if replace is a zero-string
test -z "$3" && usage
# if string is a zero-string
test -z "$4" && usage
FILE="$1"
NFILE="$2"
REGEX="$3"
STR="$4"
# set the new file equal to nothing
echo -n "" > "$NFILE"
cat $FILE | \
while read line; do
RES="" # reset RES
RES=`echo -n "$line" | grep $REGEX`# obtain result
if [ -z "$RES" ]; then # if zero-string, then line is not a match; dont replace
echo "$line" >> "$NFILE" # add to new file
else # otherwise it is a match, replace this line with the new one
echo "$STR" >> "$NFILE" #append to new file
fi
done
Save this to a file, chmod +x the file, and then run:
./script [file to modify] [new file name] [regex to search for] [replace with what]
See the result:
Code:
[frozen@Fr0ZeN frozen]$ cat test
this
is
a simple test
meow
testing
try
[frozen@Fr0ZeN frozen]$ ./script test xtest es "a whole new line"
[frozen@Fr0ZeN frozen]$ cat xtest
this
is
a whole new line
meow
a whole new line
try
Remember it's a regex. If you only provide a string, it'll replace that line if it contains that string. In order to only replace a line if it EQUALS something, do this:
./script test xtest ^es$ "a whole new line"
^ signifies the beginning of a line, $ means the end.
I noticed something you should be aware of in using the above code. Don't specify the new file as the original, otherwise ' echo -n "" > "$NFILE" ' ends up erasing all the data inside. I'll see if I can't fix that little problem.
Hold on, I'll re-edit this in a minute and post the 'real' code.
Code:
#!/bin/sh
#
# Replace lines in a file that match the given regex
# + new file can be same name as original
#
# (c) 2003 Kyle Gibson, free for non-commercial use
# may be redistributed provided this header is left
# in tact. Feel free to modify.
#
# License: GPL
##################################
usage()
{
echo "Usage: $0 [file] [nfile] [replace] [new]"
exit 1;
}
# file must be readable
test -r "$1" || usage
# the file we put this into should be specified
test -z "$2" && usage
# if replace is a zero-string
test -z "$3" && usage
# if string is a zero-string
test -z "$4" && usage
FILE="$1"
NFILE="$2"
REGEX="$3"
STR="$4"
# get the data from file
FDATA=`cat "$FILE"`
# set the new file equal to nothing
echo -n "" > "$NFILE"
echo "$FDATA" | \
while read line; do
RES="" # reset RES
RES=`echo -n "$line" | grep $REGEX`# obtain result
if [ -z "$RES" ]; then # if zero-string, then line is not a match; dont replace
echo "$line" >> "$NFILE" # add to new file
else # otherwise it is a match, replace this line with the new one
echo "$STR" >> "$NFILE" #append to new file
fi
done
#!/bin/sh
#
# Replace lines in a file that match the given regex
#
# (c) 2003 Kyle Gibson, free for non-commercial use
# may be redistributed provided this header is left
# in tact. Feel free to modify.
#
# License: GPL
##################################
usage()
{
echo "Usage: $0 [file] [nfile] [replace] [new]"
exit 1;
}
# file must be readable
test -r "$1" || usage
# the file we put this into should be specified
test -z "$2" && usage
# if replace is a zero-string
test -z "$3" && usage
# if string is a zero-string
test -z "$4" && usage
FILE="$1"
NFILE="$2"
REGEX="$3"
STR="$4"
TEMP_STORE=replace_file.$$
cat $FILE | \
while read line; do
RES="" # reset RES
RES=`echo -n "$line" | grep $REGEX` # obtain result
if [ -z "$RES" ]; then # if zero-string, then line is not a match; dont replace
echo "$line" >> "$TEMP_STORE" # add to new file
else # otherwise it is a match, replace this line with the new one
echo "$STR" >> "$TEMP_STORE" #append to new file
fi
done
mv $TEMP_STORE $NFILE
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I've been trying to work this one out for yonks but not yet been able to do it...
