On: Bash Pitfalls

[samoa42]

what is wrong with the '-i' option?

-i[SUFFIX], --in-place[=SUFFIX] edit files in place (makes backup if SUFFIX supplied)

[1vuio0pswjnm7 → samoa42]

sed -i creates a temp file. Needs additional storage space the size of the file.

This can pose a problem with large files on smaller computers with limited storage and memory.

In the past, some BSD seds (other than FreeBSD) did not have the -i option.

Also worth noting that "sponge", unlike sed, apparently reads the entire file into memory. For a large file, this would require enough RAM to fit the entire file.

[uberduper → 1vuio0pswjnm7]

Try `sed -i ""` to avoid creating a backup.

[1vuio0pswjnm7 → uberduper]

When you use sed -i, a temporary file is always created.

Using FreeBSD as an example, see references to "tmpfname" in main.c:

https://raw.githubusercontent.com/freebsd/freebsd/master/usr...

The naming scheme differs between seds. GNU prefixes the name with "sed" while BSD encloses it between two "!"'s.

To see the name of the temporary file on BSD, something like

  ktrace sed -i 's/foo/bar/' file
  kdump ktrace.out|sed -n '/NAMI/p'