Extract specific strings from line in file and output to another file with modifications

问题

New to linux and trying to escape doing this the hard way. I have a file ("output.txt") that contains the results of a 'find' command. Example first three lines from "output.txt":

/home/user/temp/LT50150292009260GNC01/L5015029_02920090917_MTL.txt
/home/user/temp/LT50150292009276GNC01/L5015029_02920091003_MTL.txt
/home/user/temp/LT50150292009292GNC01/L5015029_02920091019_MTL.txt

I'd like to use awk or sed (or similar) to extract two parts from the path listed for each line, and output to a new file ("run.txt") with extra information added on each line like so:

cd /home/user/temp/LT50150292009260GNC01; $RUNLD L5015029_02920090917_MTL.txt
cd /home/user/temp/LT50150292009276GNC01; $RUNLD L5015029_02920091003_MTL.txt
cd /home/user/temp/LT50150292009292GNC01; $RUNLD L5015029_02920091019_MTL.txt

I'm guessing this might also involve something like "cut", but I can't get my head wrapped around how to account for changing folder and file names.

Any help would be much appreciated.

回答1:

sed 's|^|cd |; s|/\([^/]*\)$|; $RUNLD \1|' inputfile > run

It says:

insert "cd " at the beginning of the line
for the last slash and what comes after, substitute "; $RUNLD " and the final part (captured by the parentheses)

回答2:

sed -e 's/^/cd /; s|/\([^/]*\)$|; \$RUNLD \1|' file

This prepends "cd " and replaces the last / with "; $RUNLD ". Voila!

回答3:

Just with bash

while IFS= read -r filename; do
  printf 'cd %s; $RUNLD %s\n' "${filename%/*}" "${filename##*/}"
done < output.txt > run

See http://www.gnu.org/software/bash/manual/bashref.html#Shell-Parameter-Expansion

回答4:

I'd probably go about this with a loop based grep solution since I don't know cut, or awk very well haha. This does the trick:

while read x; do folder=$(echo "$x" | grep -o '^.*/'); file=$(echo "$x" | grep -o '[^/]*$'); echo "cd ${folder:0:-1}; \$RUNLD $file"; done < output.txt > run

回答5:

This might work for you:

sed 's/\(.*\)\//cd \1; $RUNLD /' file
cd /home/user/temp/LT50150292009260GNC01; $RUNLD L5015029_02920090917_MTL.txt
cd /home/user/temp/LT50150292009276GNC01; $RUNLD L5015029_02920091003_MTL.txt
cd /home/user/temp/LT50150292009292GNC01; $RUNLD L5015029_02920091019_MTL.txt

来源：https://stackoverflow.com/questions/10487531/extract-specific-strings-from-line-in-file-and-output-to-another-file-with-modif

标签

bash

sed

awk

find

cut