Question

When I use grep in TEST (line 18) it works perfectly. When I do the exact same command, but inside the for-loop (line 40), it does not work. Why? I’ve bent my brain on this problem too long now.

#!/bin/bash
clear           

sourcelist=`ls *.c`
headerlist=`ls *.h`
FILE="headers.txt"

TEST="receive_elevator_data" #this is one typical entry in headers.tex
echo "TEST"
grep $TEST *.c -n

MODE="h"

if [ "$MODE" = "h" ]
then
echo "Searching.."
#for entry in $(cut -f 1 $FILE)
for entry in `cat $FILE`
    do
    echo "Looking at entry in $FILE: "
    echo $entry
    echo "Press any button to search, <s> for skip, <e> to exit"
    read -e INPUT2
    if [ "$INPUT2" = "s" ]
    then
        continue
    fi
    if [ "$INPUT2" = "n" ]
    then
        exit 1 #exit shell script
    else
        grep -n "${entry}" ${sourcelist}
    fi
done
fi

Just to clarify: every line in headers.txt has strings like “test”, i.e no space in the lines. What headers.txt really contains is a list of function names extracted from all headerfiles in a C project 🙂 There was no returned error in my previous code, it was just the grep command in the loop that wouldn’t run. What I want to do, is to search through all C files for each function in headers.txt, and prompt me before each search

Answer 1

grep probably fails because a filename contains spaces.

dont use capital letter vars. those are better used by the environment.
never try to parse ls output. use globbing instead.
if you’re writting bash, then prefer [[ over [.
do not cat file to read it. instead read it in a while loop.
always quote your variables. they’re also easier found if grouped.
treat a list of files, as an array.
if you have to use `` prefer $() which can be nested, and also quote it (foo="$(cmd ..)")

#!/bin/bash
clear           

sourcelist=(*.c)
headerlist=(*.h)
file="headers.txt"
test="receive_elevator_data" # this is one typical entry in headers.tex
mode="h"

echo "searching test"
grep -n "$test" "${sourcelist[@]}"

if [[ "$mode" == "h" ]]; then
    echo "Searching.."
    while read -r entry; do
        printf "Looking at entry in %s: %s\n" "$file" "$entry"
        read -p "Press any button to search, <s> for skip, <e> to exit" -e answer
        [[ "$answer" = "s" ]] && continue
        [[ "$answer" = "e" ]] && exit 1 # exit shell script
        grep -n "$entry" "${sourcelist[@]}"
    done < "$file"
fi