I have a for loop in bash that is;
for Names in `grep "name" $people`
do
echo "name is $name"
done
How can I have an if statement that says something like;
for Name in `grep "name" $people`
# Make sure we found some names
if [ "count of $Name=0" ]
then
echo "no names found"
fi
# Else, if we did grep out a list of names, print them
do
echo "name is $Name"
done
Add a compound conditional test (&&) to print the debug text if the for block has a return code of 0 (meaning it never got into the loop and called false):
for NAME in $(grep "name" $people)
do
echo "Name is ${NAME}"
false
done && echo "no names found"
If you don't like the way it reads, just invert the for:
! for NAME in $(grep "name" $people)
do
echo "Name is ${NAME}"
false
done || echo "no names found"
Perform the grep first and store its result in a variable. Then check whether something is returned, e.g., with wc. If so, run the loop with the result of grep.
You cannot do that inside the loop. Set a flag to true inside the loop, or check the number of arguments.
set -- `grep "$name" people`
case $# in 0) echo no names found >&2;;
*) for Name; do # special form - loop over $*
echo name is "$Name"
done ;;
esac
This might work for you:
sed -n '/name/{h;s//name is &/p};${x;/./!s/^/no names found/p}' $people
This presumes $people is a file of at least one line
EDIT: Explanation - -n prevent default printout to stdout. Search for name in each line of file $peopleand if found copy line to hold space (HS) and prepend name is to value and printout. On last line swap to HS and if it doesn't contain anything printout no names found.
A bash alternative is:
names=($(grep "name" $people))
((${#names[@]})) && printf "name is %s\n" "${names[@]}" || printf "no names found\n"
EDIT: Populate the array names with grep output. Test the size of the array names and if it is not zero, prepend name is to each value and printout else printout no names found.
