bash: How to get in the content of the 'cat' create-file command

Question

The shell script below creates a new file "foo.conf" with the content specified between the EOF tags.

#!/bin/sh
cat > foo.conf << EOF
DocumentRoot "./search.bin"
EOF

The created file contains the following content:

DocumentRoot "./search.bin"

But I need to have the full path of the current directory instead (where my shell script resides), for example:

DocumentRoot "/home/me/search.bin"

Is this even possible? Thanks in advance.

Does this answer your question? [Using variables inside a bash heredoc](https://stackoverflow.com/questions/4937792/using-variables-inside-a-bash-heredoc) — Mad Physicist, Dec 24 '19 at 19:53

score 1 · Accepted Answer · answered Dec 24 '19 at 19:51

1

Use this :

#!/bin/sh
cat > foo.conf << EOF
DocumentRoot "$(readlink -f ./search.bin)"
EOF

You can replace

readlink -f

by

realpath

answered Dec 24 '19 at 19:51

Gilles Quénot

score 0 · Answer 2 · answered Dec 24 '19 at 19:56

0

Heredocs with an unquoted first word allow for pretty much full variable and other expansion. So you can do

#!/bin/sh
cat > foo.conf << EOF
DocumentRoot "$(pwd)/search.bin"
EOF

answered Dec 24 '19 at 19:56

Mad Physicist

1

Note that `$PWD` is much faster to run than `$(pwd)`, and similarly POSIX-defined. – Charles Duffy Dec 24 '19 at 21:02
@CharlesDuffy. Thanks. TIL that PWD is a posix thing – Mad Physicist Dec 24 '19 at 21:11

2 Answers2