Issue viewing compressed file with "zless", but not with...

chef_carol

On my FreeBSD 13.2 system, the zless utility cannot view text files compressed with gzip or compress , warning that they may be binary files and then showing garbage if I say I want to see the contents anyway. Strangely, using zmore or gunzip -c seems to work. $ zless znapzend.log.1.gz "znapzend.log.1.gz" may be a binary file. See it anyway? (Answering affirmatively sends binary data to the terminal.) $ zless --version less 608 (POSIX regular...

Originally asked by Kusalananda on Stack Exchange (unix) (CC BY-SA 4.0).

uphilltech

Great question — answering as the UphillTech team:

Short story shorter: It is due to the internal pipe command being disabled when less runs in "secure" mode, i.e, LESSOPEN can't start with | if LESSSECURE is 1 . After poking at this for a while, I looked at the zless and zmore executables themselves. On FreeBSD, both are shell scripts, but while zmore is a more traditional wrapper around gzip (for decompression) and less (for viewing the decompressed document(s)), zless is a much shorter shell script calling less with the environment variable LESSOPEN set to invoke the script /usr/bin/lesspipe.sh : #!/bin/sh # # $FreeBSD$ # export LESSOPEN="||/usr/bin/lesspipe.sh %s" exec /usr/bin/less "$@" The lesspipe.sh script then consists of a case...

Full answer by Kusalananda: https://unix.stackexchange.com/a/743050 (CC BY-SA 4.0).

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