cat: invalid option — 'a'

Question

I have some c files and common.txt in "Abb/test" folder and temp.txt in "Abb" folder.I want to copy content of common.txt in header of all the c files. I am using the following unix shell script code:-

for i in 'find test -name *.c'; do cat test/common.txt $i > temp.txt && mv temp.txt $i; done

but it is giving error "cat: invalid option -- 'a' "
can someone help me out.

Answer 1

You have several grave problems in your code.

Your code with newlines for readability:

for i in 'find test -name *.c'
do
  cat test/common.txt $i > temp.txt && mv temp.txt $i
done

Problem: wrong quotes for shell substitution.

for i in `find test -name '*.c'`
do
  cat test/common.txt $i > temp.txt && mv temp.txt $i
done

Problem: not quoting $i .

for i in `find test -name '*.c'`
do
  cat test/common.txt "$i" > temp.txt && mv temp.txt "$i"
done

Problem: using for loop to loop over filenames.

find test -name '*.c' | while read -r filename
do
  cat test/common.txt "$filename" > temp.txt && mv temp.txt "$filename"
done

Answer 2

我在尝试使用cp命令执行我的自定义上传的shell脚本时遇到了类似的错误，经过大量时间搜索原因我终于发现我的脚本文件有windows line endings并在将它们转换为unix format后问题解决了。