Show all lines before a match

• Including the match,

  sed '/foo/q' file
  

  It is better to quit sed as soon as a match is found, otherwise sed would keep reading the file and wasting your time, which would be considerable for large files.

• Excluding the match,

  sed -n '/foo/q;p' file
  

  The -n flag means that only lines that reach the p command will be printed. Since the foo line triggers the quit action, it does not reach p and thus is not printed.

  • If your sed is GNU's, this can be simplified to

    sed '/foo/Q' file
    

References

1. /foo/ — Addresses
2. q, p — Often-used commands
3. Q — GNU Sed extended commands
4. -n — Command-line options

With GNU sed. Print all lines, from the first to the line with the required string.

sed '0,/foo/!d' file

Here's a solution with sed, given the content of file.txt:

bar
baz
moo
foo
loo
zoo

command including pattern

tac file.txt | sed -n '/foo/,$p' | tac

output

bar
baz
moo
foo

excluding pattern

tac file.txt | sed -n -e '/foo/,$p' | tac | sed -n '/foo/!p'

bar
baz
moo