Bash script to remove text from each line of a txt before a : - bash

Question

I have written this script to remove text from each line before ::
#!/bin/bash
txt=test.txt
COUNT=$(cat $txt | wc -l)
while [ $COUNT -gt 0 ]; do
data=$(sed -n ${count}p $txt)
sed '$count \c
"${data#*:}"' $txt
let COUNT=COUNT-1
done
I think I have an issue with using variables in commands without spaces. Can anyone tell me what I have done wrong?

Answer 1

I think you are over complicating it. To do this you just need cut:
cut -d':' -f2- file
-d sets the field separator.
-f indicates what fields to use. By saying 2- we indicate "all from the 2nd one on".
Test
$ cat a
hello
hello:man i am here:or there
and:you are here
$ cut -d':' -f2- a
hello
man i am here:or there
you are here
Some comments regarding your code:
#!/bin/bash
txt=test.txt
COUNT=$(cat $txt | wc -l) # you can directly say 'wc -l < "$txt"'
while [ $COUNT -gt 0 ]; do
data=$(sed -n ${count}p $txt) # you are using "count", not "COUNT"
sed '$count \c # same here. And I don't know what
"${data#*:}"' $txt # this sed is supposed to work like
let COUNT=COUNT-1 # you have to say let "COUNT=COUNT-1"
done
Also, it is good to indent the code, so that it shows like:
while ...
do
... things ...
done
All together, I would do:
#!/bin/bash
txt=a
count=$(wc -l < "$txt")
while (( count-- > 0 )); do
data=$(sed -n "${count}p" "$txt")
#sed '$COUNT \c "${data#*:}"' $txt # not using it
echo "${data#*:}"
done
Since you are reading the file from the bottom and done some conditions around it, you could just drop it and just use tac to print the file on reverse:
while IFS= read -r data do
echo "${data#*:}"
done < <(tac file)