Okay, I am a newbie to Unix scripting. I was given the task to find a temporary work around for this:
cat /directory/filename1.xml |sed -e "s/ABCXYZ/${c}/g" > /directory/filename2.xml
$c is a variable from a sqlplus count query. I totally understand how this sed command is working. But here is where I am stuck. I am storing the count associated with the variable in another file called filename3 as count[$c] where $c is replaced with a number. So my question is how can I update this sed command to substitute ABCXYZ with the count from file3?
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
UPDATE: In case anyone has a similar issue I got mine to work using:
rm /directory/folder/variablefilename.dat
echo $c >> /directory/folder/variablefilename.dat
d=$(grep [0-9] /directory/folder/variablefilename.dat)
sed -3 "s/ABC123/${d}/g" /directory/folder/inputfile.xml >> /directory/folder/outputfile.xml
thank you to Kaz for pointing me in the right direction
Store the count in filename3 using the syntax c=number. Then you can source the file as a shell script:
. /filename3 # get c variable
sed -e "s/ABCXYZ/${c}/g" /directory/filename1.xml > /directory/filename2.xml
If you can't change the format of filename3, you can write a shell function which scrapes the number out of that file and sets the c variable. Or you can scrape the number out with an external program like grep, and then interpolate its output into a variable assignment using command substitution: $(command arg ...) syntax.
Suppose we can rely on file3 to contain exactly one line of the form count[42]. Then we can just extract the digits with grep -o:
c=$(grep -E -o '[0-9]+' filename3)
sed -e "s/ABCXYZ/$c/g" /directory/filename1.xml > /directory/filename2.xml
The c variable can be eliminated, of course; you can stick the $(grep ...) into the sed command line in place of $c.
A file which contains numerous instances of syntax like count[42] for various variables could be transformed into a set of shell variable assignments using sed, and then sourced into the current shell to make those assignments happen:
$ sed -n -e 's/^\([A-Za-z_][A-Za-z0-9_]\+\)\[\(.*\)\]/\1=\2/p' filename3 > vars.sh
$ . ./vars.sh
you can use sed like this
sed -r "s/ABCXYZ/$(sed -nr 's/.*count[[]([0-9])+[]].*/\1/p' path_to_file)/g" path_to_file
the expression is double quoted which allow the shell to execute below and find the number in count[$c] in the file and use it as a substitute
$(sed -nr 's/.*count[[]([0-9])+[]].*/\1/p' path_to_file)
Related
I have a shell script that contains the following line
PROC_ID=$(cat myfile.sh | grep running)
which, after you echo out the value would be 1234 or something like that.
What I want to do is find and replace instances of this line with a literal value
I want to replace it with PROC_ID=1234 instead of having the function call.
I've tried doing this in another shell script using sed but I can't get it to work
STR_TO_USE="PROC_ID=${1}"
STR_TO_REP='PROC_ID=$(cat myfile.sh | grep running)'
sed -i "s/$STR_TO_REP/$STR_TO_USE/g" sample.sh
but it complains stating sed: 1: "sample.sh": unterminated substitute pattern
How can I achieve this?
EDIT:
sample.sh should contain beforehand
#!/bin/bash
....
PROC_ID=$(cat myfile.sh | grep running)
echo $PROC_ID
....
After, it should contain
#!/bin/bash
....
PROC_ID=1234
echo $PROC_ID
....
The script I'm using as described above will be taking the in an arg from the command line, hence STR_TO_USE="PROC_ID=${1}"
Simply:
sed /^PROC_ID=/s/=.*/=1234/
Translation:
At line begining by PROC_ID=
replace = to end of line by =1234.
or more accurate
sed '/^[ \o11]*PROC_ID=.*myfile.*running/s/=.*/=1234/'
could be enough
([ \o11]* mean some spaces and or tabs could even prepand)
Well, first, I want to point out something obvious. This: $(cat myfile.sh | grep running) will at the very least NOT only contain the string 1234 but will certainly also contain the string running. But since you aren't asking for help with that, I'll leave it alone.
All you need in your above sed, is first to backslash the $.
STR_TO_REP='PROC_ID=\$(cat myfile.sh | grep running)'
This allows the sed command to be terminated.
File info has some certain info on a line starting with myline. Im trying to pass it to a script like this:
bash myscript `cat info | grep myline`
This works well. Script gets "myline" as first argument. But now i want to add a "w" at the end of that. I tried
bash myscript `cat info | grep myline`w
This is already problematic, the script gets "wyline" as first argument.
And now the next step is that i actually want to have an if statement whether i want to add w or not. Tried this:
bash myscript `cat info | grep myline``[ "condition" == "condition"] && echo "w"`
This works the same way. Script gets "wyline" as first argument.
So I have two questions:
1) How to fix the "wyline" result to get desired "mylinew"
2) Is there a better way to write this if statement after cat?
Do not use backticks `, use $(...) instead. bash hackers obsolete deprecated syntax
cat file | grep is a useless use of cat useless use of cat award. Just grep file.
Just quote the result and add w:
myscript "$(grep myline info)w"
You can add a trailing w to the last line of input with sed:
myscript "$(grep myline info | sed '$s/$/w/')"
I would advise to always quote your variable expansions.
Script gets "wyline" as first argument.
Your input file has dos line endings. Inspect output with cut -v or hexdump -C or xxd. Use dos2unix and remove carriage return characters.
I made a script where the user inputs a series of letters
I wrote this for loop in my script:
#variable that contains the alphabet"
Alphabet="abcdefghijklmnopqrstuvwxyz"
#the user input
Input1=$1
#the length of the string the user inputs
lengthAlphabetInput=${#1}
for position in `seq 1 $lengthAlphabetInput`
do
letterAtPositionLength=$(($lengthAlphabetInput-$position))
letterAtPosition=$(echo "${Input1:$letterAtPositionLength:1}")
alphabetAtPositionLength=$(($lengthAlphabetInput-$position))
alphabetAtPosition=$(echo "${Alphabet:$alphabetAtPositionLength:1}")
sed "s/$alphabetAtPosition/$letterAtPosition/g" file.txt
done
I expected that if the user inputs
./script.sh xyz
that it would change every
a with an x
b with an y
c with a z
but instead it only replaces every a with an x. It skips the rest for some reason.
Can anyone help me out?
Your sed command isn't saving the result anywhere, just printing it to stdout. If you have GNU sed you can use the -i flag to modify the file in place. E.g.:
sed -i "s/$alphabetAtPosition/$letterAtPosition/g" file.txt
otherwise you can write the results to a temporary file and copy it back:
tmp_file=$(mktemp)
sed "s/$alphabetAtPosition/$letterAtPosition/g" file.txt > "$tmp_file"
mv -f "$tmp_file" file.txt
Other versions of sed may have similar flags to -i though, so check your man page for local options.
Your script will benefit from the y command of sed, which does exactly what you want:
$ echo abcdef > a
$ sed 'y/abc/xyz/' a
xyzdef
Quoting the man page:
y/source/dest/
Transliterate the characters in the pattern space which appear
in source to the corresponding character in dest.
Here's how you could use sed y in your script:
letters="abcdefghijklmnopqrstuvwxyz"
replacement="$1" # don't forget the quotes!
letters="${letters:0:${#replacement}}"
sed -i "y/${letters}/${replacement}/" file.txt
Note how this solution requires no loops and reads/writes the file only once.
I have a large number of words in a text file to replace.
This script is working up until the sed command where I get:
sed: 1: "*.js": invalid command code *
PS... Bash isn't one of my strong points - this doesn't need to be pretty or efficient
cd '/Users/xxxxxx/Sites/xxxxxx'
echo `pwd`;
for line in `cat myFile.txt`
do
export IFS=":"
i=0
list=()
for word in $line; do
list[$i]=$word
i=$[i+1]
done
echo ${list[0]}
echo ${list[1]}
sed -i "s/{$list[0]}/{$list[1]}/g" *.js
done
You're running BSD sed (under OS X), therefore the -i flag requires an argument specifying what you want the suffix to be.
Also, no files match the glob *.js.
This looks like a simple typo:
sed -i "s/{$list[0]}/{$list[1]}/g" *.js
Should be:
sed -i "s/${list[0]}/${list[1]}/g" *.js
(just like the echo lines above)
So myFile.txt contains a list of from:to substitutions, and you are looping over each of those. Why don't you create a sed script from this file instead?
cd '/Users/xxxxxx/Sites/xxxxxx'
sed -e 's/^/s:/' -e 's/$/:/' myFile.txt |
# Output from first sed script is a sed script!
# It contains substitutions like this:
# s:from:to:
# s:other:substitute:
sed -f - -i~ *.js
Your sed might not like the -f - which means sed should read its script from standard input. If that is the case, perhaps you can create a temporary script like this instead;
sed -e 's/^/s:/' -e 's/$/:/' myFile.txt >script.sed
sed -f script.sed -i~ *.js
Another approach, if you don't feel very confident with sed and think you are going to forget in a week what the meaning of that voodoo symbols is, could be using IFS in a more efficient way:
IFS=":"
cat myFile.txt | while read PATTERN REPLACEMENT # You feed the while loop with stdout lines and read fields separated by ":"
do
sed -i "s/${PATTERN}/${REPLACEMENT}/g"
done
The only pitfall I can see (it may be more) is that if whether PATTERN or REPLACEMENT contain a slash (/) they are going to destroy your sed expression.
You can change the sed separator with a non-printable character and you should be safe.
Anyway, if you know whats on your myFile.txt you can just use any.
I have variable which has value "abcd.txt".
I want to store everything before the ".txt" in a second variable, replacing the ".txt" with ".log"
I have no problem echoing the desired value:
a="abcd.txt"
echo $a | sed 's/.txt/.log/'
But how do I get the value "abcd.log" into the second variable?
You can use command substitution as:
new_filename=$(echo "$a" | sed 's/.txt/.log/')
or the less recommended backtick way:
new_filename=`echo "$a" | sed 's/.txt/.log/'`
You can use backticks to assign the output of a command to a variable:
logfile=`echo $a | sed 's/.txt/.log/'`
That's assuming you're using Bash.
Alternatively, for this particular problem Bash has pattern matching constructs itself:
stem=$(textfile%%.txt)
logfile=$(stem).log
or
logfile=$(textfile/%.txt/.log)
The % in the last example will ensure only the last .txt is replaced.
The simplest way is
logfile="${a/\.txt/\.log}"
If it should be allowed that the filename in $a has more than one occurrence of .txt in it, use the following solution. Its more safe. It only changes the last occurrence of .txt
logfile="${a%%\.txt}.log"
if you have Bash/ksh
$ var="abcd.txt"
$ echo ${var%.txt}.log
abcd.log
$ variable=${var%.txt}.log