zsh 4.3.4% cat file
34
45
56
77
55
66
54
67
zsh 4.3.4% eval printf "%d\\\n" $(printf "\$((%d-1)) " $(<file))
33
44
55
76
54
65
53
66

zsh 4.3.4% awk '$1=$1-1' file
33
44
55
76
54
65
53
66