Am 13.08.21 23:19 schrieb Philippe Meunier: > Hello, > > While porting a shell script from Linux to OpenBSD I came across the > following: > > $ uname -a > Linux foo.there.org 3.10.0-1127.19.1.el7.x86_64 #1 SMP Tue Aug 25 17:23:54 > UTC 2020 x86_64 x86_64 x86_64 GNU/Linux > $ cat > foo > test > hello > world > $ sed '0,1d' < foo > sed: -e expression #1, char 4: invalid usage of line address 0 > $ sed '0,/^hello$/d' < foo > world > $ sed '1,/^hello$/d' < foo > world > $ sed '0,/^test$/d' < foo > hello > world > $ sed '1,/^test$/d' < foo > $ > > which makes sense since, according to > https://www.gnu.org/software/sed/manual/html_node/Addresses.html: > > [...] > 0,/regexp/ > A line number of 0 can be used in an address specification like 0,/regexp/ > so that sed will try to match regexp in the first input line too. In other > words, 0,/regexp/ is similar to 1,/regexp/, except that if addr2 matches > the very first line of input the 0,/regexp/ form will consider it to end > the range, whereas the 1,/regexp/ form will match the beginning of its > range and hence make the range span up to the second occurrence of the > regular expression. > Note that this is the only place where the 0 address makes sense; there is > no 0-th line and commands which are given the 0 address in any other way > will give an error. > [...] > > Now: > > $ uname -a > OpenBSD bar.here.org 6.8 GENERIC#0 i386 > $ cat > foo > test > hello > world > $ sed '0,1d' < foo > test > hello > world > $ sed '0,/^hello$/d' < foo > test > hello > world > $ sed '1,/^hello$/d' < foo > world > $ sed '0,/^test$/d' < foo > test > hello > world > $ sed '1,/^test$/d' < foo > $ > > So: > > 1) I'm surprised that '0,1d' and '0,/^hello$/d' and '0,/^test$/d' don't give > an error. Looking at the results, I'm not sure what they do, if anything. > > 2) Out of curiosity, is there an OpenBSD equivalent to GNU's '0,/^test$/d' ?
Your first address is 0? What do you expect from a line number 0? You can do: sed '/^test$/d' OR sed 1d OR grep -v 'test' OR ... > > Thanks, > > Philippe > >
