41

How can I get to stdout all commands that run in bash script?

That is output must contain commands output AND commands themselves.

I found

#!/bin/bash -x

but this is not exactly the same because instead of

 mysql -v dbname < dump.sql | grep "CREATE TABLE"

it shows

+ mysql -v dbname
+ grep 'CREATE TABLE'

3 Answers 3

42

Use bash -v.

This is the script:

#!/bin/bash -v

echo "Hello, World" | sed 's|Hello|Goodbye|'

echo "Done."

This is the output:

#!/bin/bash -v

echo "Hello, World" | sed 's|Hello|Goodbye|'
Goodbye, World

echo "Done."
Done.

Unfortunately, there is no special marker like PS4 for printing expanded commands. You could combine both though to quickly identify commands:

#!/bin/bash -vx

echo "Hello, World" | sed 's|Hello|Goodbye|'
+ echo 'Hello, World'
+ sed 's|Hello|Goodbye|'
Goodbye, World

echo "Done."
+ echo Done.
Done.
19

set -x is other way of doing it.

$ cat a.sh
#!/bin/bash

set -x
echo "Hello, World" | sed 's|Hello|Goodbye|'
echo "Done."

Output will be:

sh a.sh
+ echo 'Hello, World'
+ sed 's|Hello|Goodbye|'
Goodbye, World
+ echo Done.
Done.
4
  • 2
    Which is kind of what the OP dismissed as useless right in his question...
    – Daniel Beck
    Feb 7, 2012 at 18:12
  • @Ashok Could you please explain? I can't see the difference: here p.s.: GNU bash, version 4.1.5(1)-release (i486-pc-linux-gnu) Ubuntu 10.04.3
    – Putnik
    Feb 8, 2012 at 13:49
  • 1
    @Putnik It's the same basic thing, but you can set -x anywhere in the script, and even deactivate it again. So if you only want it on the echo "Done" line, put set -x just before that one.
    – Daniel Beck
    Feb 8, 2012 at 15:09
  • landed here through a search engine, found your answer helpful. Thx
    – studioj
    Nov 1, 2021 at 19:22
7

set -x is an equivalent of "echo on"

set +x is an equivalent of "echo off"

1
  • landed here through a search engine, found your answer helpful. Thx
    – studioj
    Nov 1, 2021 at 19:22

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