Using 'if' within a 'while' loop in Bash

I have these diff results saved to a file: ``` bash-3.00$ cat /tmp/voo 18633a18634 > sashabrokerSTP 18634a18636 > sashatraderSTP 21545a21548 > yheemustr ``` I just really need the logins: ``` bash-3.00$ cat /tmp/voo | egrep ">|<" > sashaSTP > sasha > yhee bash-3.00$ ``` But when I try to iterate through them and just print the names I get errors. I just do not understand the fundamentals of using "if" with "while loops". Ultimately, I want to use the `while` loop because I want to do something to the lines - and apparently `while` only loads one line into memory at a time, as opposed to the whole file at once. ``` bash-3.00$ while read line; do if [[ $line =~ "<" ]] ; then echo $line ; fi ; done < /tmp/voo bash-3.00$ bash-3.00$ bash-3.00$ while read line; do if [[ egrep "<" $line ]] ; then echo $line ; fi ; done < /tmp/voo bash: conditional binary operator expected bash: syntax error near `"<"' bash-3.00$ bash-3.00$ while read line; do if [[ egrep ">|<" $line ]] ; then echo $line ; fi ; done < /tmp/voo bash: conditional binary operator expected bash: syntax error near `|<"' bash-3.00$ ``` There has to be a way to loop through the file and then do something to each line. Like this: ``` bash-3.00$ while read line; do if [[ $line =~ ">" ]]; then echo $line | tr ">" "+" ; if [[ $line =~ "<" ]]; then echo $line | tr "<" "-" ; fi ; fi ; done < /tmp/voo + sashab + sashat + yhee bash-3.00$ ```