On Sat, 28 Sep 2024 at 17:44:03 Alexander Jones wrote: | On Sat, 28 Sep 2024 at 23:59:55 Artyom Bologov wrote: | | To edit a file with a | | script taken from another file, one has to do | | | | ed input.txt < script.txt | | | | which is unintuitive, I believe. What if it was this? | | | | edscript script.txt input.txt | | | | I find this more logical—we run ed script upon the file. | | I think a flag akin to the -f flag on AWK would be better. (edscript could | possibly alias "ed -f" in that example.) I could also envision using GNU | ed's comment handling on '#' to enable shebangs in script files, though I | admit it would not be portable.
For anyone interested in scripting with ed, please consider: <https://github.com/slewsys/ed>. Antonio has hinted that he intends to adopt some of its capabilities, which include the options -f and -e, external filters, the ability to edit the output of named pipes, multiple-file support, registers, etc. This implementation of ed also happens to be more compatible with both traditional ed and OpenGroup's (SUSv4) ed and has a much more robust testsuite. Some examples: $ cat upcase.ed #!/usr/bin/env -S ed -f ,! tr a-z A-Z ,p $ ed -f upcase.ed <(cal) DECEMBER 2024 SU MO TU WE TH FR SA 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 $ Here, ed reads from named pipe `<(cal)' to the editor buffer and takes commands from the file `upcase.ed'. The ed command `,! tr a-z A-Z' writes the buffer as standard input to Unix filter `tr', whose output replaces written buffer lines. GNU ed is not able to read from named pipes like that; it's not able to filter buffer lines via external commands; it doesn't support option -f. The principle advantage of option -f is that one can write pure ed scripts: $ chmod +x upcase.ed $ ./upcase.ed <(cal) DECEMBER 2024 SU MO TU WE TH FR SA 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 $ Another scripting feature adopted from sed is option -e, which allows writing the upcase script on the command line: $ ed -e ',!tr a-z A-Z' -e ',p' <(cal) DECEMBER 2024 SU MO TU WE TH FR SA 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 $ Again, GNU ed does not yet support option -e. Yet another important scripting feature inpsired by `sed' is support for multiple files: $ cat file1.txt hello, world! $ cat file2.txt now is the time $ ./upcase.ed *.txt HELLO, WORLD! NOW IS THE TIME $ An extension inspired by `ex' is registers to copy-and-paste between files: $ ed -p '* ' file1.txt 14 * t> * e file2.txt 16 * <t * ,p now is the time hello, world! * wq $ cat file2.txt now is the time hello, world! $ The ed commands `t' and `m' copy and move, respectively, lines from a source to a destination. Using `>' here as the destination copies (the current line) to a default register. In the second file, `<t' copies from the default register to after the current line in the buffer. And the list goes on. What this implementation of ed does not adopt is the branching constructs of sed `b', `t' and `T' since ed has enough strengths without, and higher-level scripting languages like `awk' are easier to work with. -AM
