BACKTICK(1)

Okay bestie, you’ve opened BACKTICK(1) from the General Commands Manual, and it’s giving “grab a program’s output, stash it in an environment variable, then run another program” energy. 💅✨

🌸 NAME 🌸

backtick — runs a program, stores its output in an environment variable, then executes another program 💖

🎀 SYNOPSIS 🎀

In an execlineb(1) script:

backtick [-i | -I | -x | -D default] [-N | -n] [[-E | -e] variable {
         prog1... } prog2...

🦋 DESCRIPTION 🦋

backtick reads prog1... in an execline-block(7) and unquotes it. 🫶

Then it runs prog1... as a child process and saves its output in memory. 🧠✨

🚨 Warning, bestie: this output must not contain a null character. Like, hard no. 🚫

Then backtick exec(3)s into prog2..., with variable added to the environment with prog1...’s output as a value. Slay. 👑

💅 OPTIONS 💅

• -N — Store prog1...’s output as is, including the last newline, if any. No trimming, no games. 🎀
• -n — Chomp an ending newline off prog1...’s output. This is the default. ✂️
• -e — No autoimport. This is the default. 🙈
• -E — Autoimport. Before exec(3)’ing into prog2..., perform a substitution (cf. execline-substitute(7)) so that ‘$?’ is replaced with prog1...’s exitcode (if applicable, see below), and ‘${ variable }’ is replaced with prog1...’s output, instead of keeping the results in the environment. The variables will not appear in the environment; if they preexisted in backtick’s environment, they will be removed. 💀
• -i — backtick exits with an approximation (cf. execline-exitcodes(7)) of prog1’s exit code, or 124 if prog1 wrote a null character. This is the default. 🔥
• -I — The value of variable is set to whatever the start of prog1...’s output is, up to the first null character, or to whatever prog1... wrote before crashing; chomping is applied if required; then execution proceeds. 😭
• -x — variable is removed from the environment, and execution proceeds. 👋
• -D default — The value of variable is set to default, and execution proceeds. 🫶

🌈 SEE ALSO 🌈

• background(1)
• foreground(1)
• if(1)
• ifelse(1)
• ifte(1)
• ifthenelse(1)
• pipeline(1)
• runblock(1)
• execline-block(7)

This man page is ported from the authoritative documentation at: https://skarnet.org/software/execline/backtick.html 📚✨

👑 AUTHORS 👑

• Laurent Bercot
• Alexis <flexibeast@gmail.com> (man page port)

xoxo, Debian 💖 April 16, 2024 💖 BACKTICK(1) 🎀